Editor’s Note: This week we’re at the virtual 238th AAS Meeting. Along with a team of authors from Astrobites, we will be writing updates on selected events at the meeting and posting each day. Follow along here or at astrobites.com. The usual posting schedule for AAS Nova will resume on June 14th.

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SPD George Elery Hale Prize Lecture: The Evolution of Our Understanding of Coronal Mass Ejections (by Tarini Konchady)

This year’s recipient of the Hale Prize is Russell Howard (Naval Research Laboratory), for “his influential contributions to the discovery, measurement, and physical understanding of coronal mass ejections and their role in space weather, and for his outstanding leadership in the development, deployment, and management of innovative space instrumentation to image the solar corona and inner heliosphere”. Quite aptly, Howard’s talk was titled “The Evolution of Our Understanding of Coronal Mass Ejections”.

Coronal mass ejections (CMEs) are the expulsion of plasma and the associated magnetic fields from near the Sun’s surface. They are extremely fast, and a single CME could cause catastrophic damage if it hit the Earth. However, our study of CMEs started fairly recently. In fact, Howard joined the Naval Research Laboratory only three months before the first observations of a CME, which was in 1971. And even then, “coronal mass ejection” didn’t enter the vocabulary of solar physics till the 1980s.

Howard outlined the history of CME science in the context of the various solar instruments that have been used to study CMEs. The first generation of instruments were on the Orbiting Solar Observatory 7 (OSO-7) and the space station Skylab. OSO-7 gave us the first observation of a CME, while Skylab produced a large sample of CME observations that would create the archetype of the event. The next generation of instruments was on the Solar Maximum Mission (SMM) and Solwind, also known as P78-1. The observations taken by the instruments on these missions let us study the evolution of CMEs more closely and identify correlations between CMEs and properties like X-ray emission and sunspot occurrence.

The third generation of instruments arrived in the 1990s and included instruments on the Solar and Heliospheric Observatory (SOHO), the Solar Terrestrial Relations Observatory (STEREO), and the Parker Solar Probe. One of the most significant advances with this generation was that instruments could observe the Sun continuously. With these new data, we were able to understand the magnetic fields associated with CMEs by using observations to inform models of electron density.

We’re still in the third generation of solar instruments and there still remain many questions to be answered. For instance, how do CMEs travel through space and how could they impact the Earth? What instabilities in the Sun create CMEs? With this latest set of instruments, the answers could arrive sooner than we think!

Live-tweeting of the session by Tarini Konchady

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Press Conference: Fast Radio Bursts / Exoplanets & Brown Dwarfs (by Sabina Sagynbayeva)

The first press conference of Day 3 was emceed by none other than astrobites author Luna Zagorac, who is serving as the Astrobites Media Intern for AAS 238. Luna introduced panelists presenting on two very different topics: fast radio bursts (FRBs), and exoplanets/brown dwarfs.

Kiyoshi Masui (MIT) started off the discussion with “Fast Radio Bursts: From a Handful to Hundreds with CHIME/FRB.” The first FRB — a mysterious and brief flash of radio light usually stemming from outside our galaxy — was discovered in 2007; since then, 535 FRBs have been observed and put into the The Canadian Hydrogen Intensity Mapping Experiment (CHIME) catalog! CHIME has opened a new phase of FRB science, enabling precision studies of the FRB population and an opportunity to study large-scale structure of the universe. Following the discussion, Alex Josephy (McGill University) talked about population modelling. His group works on understanding observational biases by simulating fake bursts and analyzing observational factors like sensitivity, telescope response, and the galactic foreground. After correcting for these effects, they found strong evidence of a uniform FRB distribution. Finally, Mohit Bhardwaj (McGill University) talked about FRB20181030A, a repeating FRB in the CHIME/FRB catalog. This FRB is localized to a sky area ~140x smaller than the Moon in the sky! Press release

Jacob Nibauer (University of Pennsylvania) next pivoted to planets with “A Statistical Search for Chemical Signatures of Planet Formation in Sun-like Stars.” Thus far, we’ve primarily identified exoplanets by examining a star’s radial velocity, and by looking for transits. But we can also look at the chemical composition of the star! If rocky planets were formed in circumstellar disks around the star, then the star might have less refractory material (rocky material) than the star without planets (in this case all the refractory material will be eaten by the star). Nibauer and collaborators used data from APOGEE-2 to examine 1,500 Milky Way stars and categorize them as “depleted” or “not depleted” of refractory material. In so doing, they showed that our own Sun is a member of a majority population (>60%) of depleted stars — not far off from the estimated fraction of stars with rocky planets. These two populations may therefore be related to the presence/absence of rocky planets. Press release

Tarun Kota (Eastview High School) is a high-school student who talked about looking for faint motion objects with CatWISE2020! Kota presented three new discoveries: two M dwarfs, and one extremely faint, cold brown dwarf. How did he and his collaborators search through 1.9 billion objects in CatWISE to arrive at a conclusion? The answer: machine learning! Kota’s network successfully narrowed the catalog down to 6,000 high-interest candidates. Because CatWISE has only one color (W1-W2), they then had to match to other infrared databases to make the selection of truly unique objects. Rounding out his talk, Kota also reminded us that now the general public has an opportunity to do research in astrophysics through citizen science! Additional info

YouTube recording of the session on the AAS Press Office channel
Live-tweeting of the session by Sabina Sagynbayeva

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SPD Agency Town Hall (by Luna Zagorac)

The Solar Physics Division (SPD) Agency Town Hall began with updates from the National Science Foundation (NSF), courtesy of Carrie Black. Black encouraged folks to submit solar physics proposals to the Astronomical Sciences (AST) division of NSF as the division is proposal-driven: this means that increasing numbers of solar proposals will result in increased funding for solar physics research! Now would be a particularly good time to submit any solar eclipse proposals. Black also plugged NSF’s Astronomy and Astrophysics Postdoctoral Fellowships as an opportunity to fund solar research. She also noted that it’s been a tough year for AST between COVID impacts and absorbing most of the Arecibo cleanup costs. However, there are also new programs within AST to help severely impacted groups, including people who are at transition points in their careers. Black concluded by looking forward to decadal surveys, including Astro2020 this summer and the Solar and Space Physics (SSP) decadal.

Next, Nicola Fox of NASA’s heliophysics division announced that the division is experiencing incredible growth. She also thanked everyone who participated in the Helio 2050 Workshop held in early May 2021, and encouraged everyone to keep the discussion sparked there going into the next decadal. She further noted that IDEA initiatives are being recognized as a long-term effort, but immediate action and problems are considered and incentivized as well. Finally, she reminded everyone that they can stay informed through her monthly “Nicky Notes” from (sign up here), as well as by checking the NASA Town Hall website.

Updates from the Daniel K. Inouye Solar Telescope (DKIST) were delivered by Valentín Martinez Pillet. He noted that the observatory staff are still mostly working from home, but construction is moving forward while respecting COVID restrictions. Because of this, DKIST’s construction is expected to end in November 2021. Furthermore, Martinez Pillet noted that there will be a second round of soliciting observing proposals for DKIST, but the date is not set yet; one way of staying in the loop is to sign up for updates here.

Finally, Holly Gilbert updated us on the High-Altitude Observatory (HAO), the solar-terrestrial research laboratory of the National Center for Atmospheric Research (NCAR). The research program of HAO is broad, spanning from the origins of magnetism in the Sun to the upper edge of the terrestrial stratosphere. HAO runs several cutting-edge instruments, including the COSMO K-Coronagraph (K-COR) on the Mauna Loa Solar Observatory (MLSO), as well as COMP, the coronal multi-channel polarimeter. These instruments are designed to carry out synoptic large-scale observations of the Sun’s magnetic activity. COMP was used, for the first time, to map the global coronal magnetic field of the Sun! These, along with upcoming instruments (e.g, ChroMag & the Large Coronagraph) will hopefully expand our understanding of solar magnetic fields. Finally, Gilbert noted that the next NCAR/HAO workshop will take place Sept 12–17, 2021; stay tuned here.

Live-tweeting by Luna Zagorac

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Astro2020 Advocacy, Satellite Constellations, and More! Town Hall (by Macy Huston)

The AAS Policy Town Hall covered current issues in science and space policy. Megan Donahue began with an introduction to CAPP (the Committee on Astronomy and Public Policy), which supports and develops policies that advance the astronomical sciences in the United States. They are involved in the Decadal Survey process, in which the astronomy community reviews the state of the science and makes recommendations for relevant funding agencies. CAPP’s advocacy plans include coordinating a task force and arranging communications between survey leaders and government members and agencies.

The pandemic-related delays in the Decadal Survey have pushed back budget planning. The FY22 and 23 budgets had to be created without the report, but it will be incorporated in FY24 plans. AAS/CAPP will release a statement about the report, encouraging the community to avoid in-fighting, analyzing timelines and budgets, and supplying talking points for those who communicate with policymakers. The NSF has received a funding increase of 20% in the president’s FY 2022 budget request, and NASA received a bump as well. CAPP aims to get specific mentions of astronomical priorities in relevant bills and agency plans.

Richard Green represented the Light Pollution, Radio Interference, and Space Debris (LPRISD) Committee, which gathers and provides info on these topics and works to combat the problems. A particular focus lately has been satellite constellations. Optically, the current versions of SpaceX Starlink and OneWeb constellations are mostly invisible to the eye, but they still pose a major concern for large telescopes. These constellations, as well as commercial activities being planned on the Moon, threaten the existence of radio-quiet zones, both on Earth (e.g., for the Green Bank Telescope) and on the shielded zone of the Moon.

The UN Office of Outer Space Affairs (UNOOSA) and the International Astronomical Union (IAU) are working on international policies and collaborations to address these issues. The AAS has made a case for studying the science impacts of space debris, and the FCC recently stated that these science impacts should be considered in their rulings. Modelling is currently in progress to determine under what circumstance a space debris runaway (a progressive series of collisions in orbit that produce exponentially increasing debris) could occur, devastating prospects for astronomy and spaceflight. The SATCON2 Workshop (July 12–16) will work to address the problem of satellite constellations. In addition to these issues, Artificial Light At Night (ALAN) on Earth’s surface remains a long term threat to ground-based observatories. The IAU and UNOOSA are planning a workshop on Dark and Quiet Skies for the Fall of 2021.

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Plenary Lecture: The Complex Upper H-R Diagram – Shaped by Mass-Loss (by Ellis Avallone)

The second to last plenary of AAS 238 was all about the fate of massive stars. Dr. Roberta Humphreys (University of Minnesota) is an expert on stars in the upper Hertzsprung–Russell (HR) diagram, a region that encompasses the most massive stars in our universe. One of the most exciting things about these massive stars is that their relatively short lifetimes mean that they can undergo extreme changes on the order of human timescales (tens of years).

Back in the 1970s, Dr. Humphreys and her colleagues noticed that massive stars had a linear upper limit on their brightness. This was the first clue that mass loss, specifically extreme mass loss events, were taking place as massive stars moved into the late stages of their evolution. When the 1990s rolled around and Hubble was launched, we were able to get incredibly detailed observations of mass loss in evolved massive stars!

Dr. Humphreys moved on to describe a fan favorite example of stellar mass loss, the red hypergiant VY CMa, which she dedicated to the late Dr. George Wallerstein, founder of the University of Washington Astronomy Department and VY CMa enthusiast. VY CMa is an incredibly well-observed star, with lightcurve observations going back to the 1800s! Thanks to a combination of observations from Keck, Hubble, and ALMA, we now know that gaseous outflows both account for and explain the mass loss experienced by this star. These gaseous outflows are likely shaped and supported by magnetic fields.

Many stars in this regime are also pulsationally unstable, exhibiting periodic variability both in their lightcurves and spectra. Luminous Blue Variables (LBVs) are one such class of star that exist in super close proximity to the Eddington limit, the theoretical upper limit on a star’s luminosity. It’s thought that the mass loss events experienced by these stars are triggered when they exceed the Eddington limit and become unstable.

Dr. Humpreys concludes her talk by discussing another class of mass-loss-experiencing stars: failed supernovae. These stars undergo incredibly explosive mass loss events that are often mistaken in supernovae due to their brightness. However, their spectra reveal key differences that distinguish them from true supernovae. One famous example of a failed supernova is Eta Carinae, which underwent a sudden brightening and dimming event in the 1850s and has been growing steadily brighter ever since. Who knows what the next 50 years will bring from these wild and exciting stars!

Interview of Roberta Humphreys by Sabina Sagynbayeva
Live-tweeting of the session by Ellis Avallone

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LAD Early Career Award: From Atoms To Black Holes: Modeling Dense Astrophysical Plasmas (by Sabina Sagynbayeva)

Javier García (Caltech) is the 2021 recipient of the Laboratory Astrophysics Division’s Early Career Award. García’s career has spanned a broad range of contributions to computational atomic physics and high-energy photoionization/spectral modeling. Accordingly, his plenary touched on the variety of ways we can model dense astrophysical plasmas.

Background X-ray sources are valuable means to characterize absorbing material in the line of sight, García mentions, but this process relies on a thorough understanding of the atomic physics at work! By cross-comparing theoretical calculations of absorption lines, data from laboratory experiments, and actual observations from X-ray observatories like Chandra and XMM-Newton, scientists are able to perform benchmarking to make sure the right parameters are used in the models and the instruments are calibrated correctly.

Another way we can use X-ray atomic lines is via reflection spectroscopy. By exploring the reflected X-ray spectra from accreting black holes, we can obtain estimates of their spins — if we have a good model! Future work in this field will rely both on increasingly better data — e.g., from Athena, a future X-ray observatory — and on improving the atomic physics included in the models. In accretion-disk microphysics, typical reflection models are calculated for low densities, but to accurately model the plasma environment around a black-hole binary or an active galactic nucleus, we also need to account for high-density plasma effects.

García concludes that X-ray reflection spectroscopy provides the best means to estimate black-hole spin, among many other parameters. Astrophysical observations give access to the best laboratories in the universe that can be used to calibrate models and learn about atomic structure. While the future is X-ray bright (with new observatories like XRISM, IXPE, Athena, and eXTP planned), we need to be prepared. Lab Astro will play a fundamental role!

Live-tweeting of the session by Sabina Sagynbayeva

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Press Conference: Exoplanets & Brown Dwarfs (by Susanna Kohler)

The final press conference of the meeting supplemented the previous briefing with even more presentations on exoplanets and brown dwarfs.

First up: a look at Kepler’s K2 mission, the gift that just keeps giving. After Kepler experienced a technical failure in 2013, intrepid scientists proposed the revised mission K2, in which the telescope, no longer fully stabilized, would instead be used to search a much larger area at lower depth. This remarkably successful salvage ran for more than four years, and we’re still reaping the rewards: the rich dataset produced during K2 continues to be mined for more discoveries!

So far, the majority of the 889 planet candidates discovered in K2 data have resulted from visual inspection due to the noisy data. But Jon Zink (University of California, Los Angeles) reported on 372 brand new planet candidates recently produced by an automated detection pipeline. This large dataset — produced in a uniform way and spanning a large area on the sky — is perfect for exploring population statistics.

Sakhee Bhure (Florida Institute of Technology) then talked about the next step: validating these candidates. To become a confirmed planet, a candidate must have its mass measured — a challenging process. But there’s another way to establish the legitimacy of a candidate: we can statistically validate it by calculating the likelihood that the transit shape in its light curve is produced by a true planet rather than by some other source. Bhure presented VESPA, a tool developed by Dr. Timothy Morton that performs this analysis and assigns a likelihood to a candidate’s legitimacy. She then walked us through a few of the 21 planets that VESPA has newly validated.

Next up, Elena Manjavacas (Space Telescope Science Institute) presented recent spectroscopic observations that probe the different cloud layers of a nearby brown dwarf. Why are brown dwarfs of interest? These small, failed stars are often close analogs of large gas-giant exoplanets — and, because they’re free-floating instead of bound to a bright star, they’re easier to observe. By studying brown dwarfs, we can therefore learn more about the atmospheres of giant exoplanets. Manjavacas and collaborators were able to map out parts of the brown dwarf’s complex atmosphere, showing the chemical composition of the clouds in different layers. Press release

Concluding the session, Jason Curtis (Columbia University) told us the story of how two seemingly old and unrelated exoplanet systems turned out to be rather young siblings. Kepler 52 and Kepler 968 are two stars — each hosting three planets — that were thought to be isolated and old, with ages estimated at 3–16 billion years (that huge range should tell you how hard it is to measure stellar ages!). New work by Curtis and collaborators has now shown that these two systems are actually both part of the same newly discovered cluster of stars called Theia 520. By exploring the rotation rates of the stars, the team was able to associate these stars with one another and age the cluster at just ~350 million years old. Press release (PDF)

YouTube recording of the session on the AAS Press Office channel

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Astrobites Webinar (by Macy Huston)

We had our Astrobites webinar today, in which panelists Luna Zagorac, Mia de los Reyes, and Sabina Sagynbayeva introduced who we are and how people can get involved. Astrobites is the astro-ph “Reader’s Digest.” We are supported by the AAS and share daily “bite-sized” paper summaries accessible to undergraduate astronomy students. We are an international collaboration of graduate students, with 41 authors currently, typically on 2-year rotations.

Our bites generally contain background on the covered paper’s topic, a summary of its results, and relevant figures. We try to avoid jargon (or we provide links to more info when we have to use it), and the summaries are typically between 600–1000 words. In addition to paper summaries, we also write “Beyond” posts, which cover topics like diversity, equity, and inclusion, day-to-day work advice, current event coverage (like this!), and career/application advice.

So how can you get involved? Undergraduates are invited to submit their research to be published on our site. Graduate students can apply to be an Astrobites author; we accept applications every year, typically due in November. Graduates students (as well as others, e.g., post-bac researchers) are invited to submit a guest post. Educators are invited to use Astrobites for reading assignments, source material, or writing assignment examples. We also have a paper about using Astrobites in the classroom, which includes free lesson plans. Also, check out our sister sites for Astrobites in a few languages besides English: Astrobitos (Spanish), Astropontos (Portuguese), staryab (Farsi), and ArAStrobites (Arabic).

Lastly, our panelists answered some questions, both pre-prepared and sourced from the audience. What they love about being a part of Astrobites is the supportive and collaborative community, as well as the networking opportunities it provides. Asked about our collaboration structure, we clarified the non-hierarchical organization. We are a group of writers who peer-edit on a rotating schedule. AAS sponsors us, but they don’t have editorial control over our work. We have a set of committees made up of members who opt to take part in them, for example the Diversity, Equity, and Inclusion Committee and the Scheduling Committee. Our panelists wanted to join astrobites because of past experiences with finding the paper summaries helpful and enjoying writing a guest post. A few things they would like to see in the future of Astrobites are more collaboration with our sister sites to translate posts, expansion of the Black in Astro series, gaining more international participation beyond the US and Europe, and including more languages.

Live-tweeting of the session by Macy Huston

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Plenary Lecture: Science Highlights from the Nuclear Spectroscopic Telescope Array (NuSTAR) (by Luna Zagorac)

The last plenary of AAS238 was delivered by Daniel Stern (NASA JPL). Stern spoke about science highlights from the Nuclear Spectroscopic Telescope Array (NuSTAR) — a NASA Small Explorer mission that launched 9 years ago, during the last AAS meeting scheduled in Anchorage, AK. NuSTAR is an X-ray telescope that observes high energies comparable to ones used in doctors’ and dentists’ instruments. It is also the first focusing X-ray satellite, meaning that the images it produces are sharper and have lower background levels than its predecessors.Three key technologies enabled NuSTAR: a cadmium-zinc-tellurium detector, a deployable mast (which allowed NuSTAR to launch on a smaller rocket and then unfurl once in orbit!), and hard-X-ray optics.

Stern went on to discuss some of the big scientific results that have come about from this relatively small instrument. The first breakthrough had to do with ultraluminous X-ray sources (ULXs), a class of objects whose identity has been a mystery since the first ULX was detected by the Einstein Observatory in the ‘80s. Since most X-rays come from the accretion of material onto black holes, ULXs were posited to be either (very rare) intermediate-mass black holes feeding at typical rates, or stellar-mass black holes feeding at prodigious rates. NuSTAR somewhat unwittingly contributed to the unveiling of ULXs while observing supernova SN2014J: it also observed two ULXs at the center of the galaxy M82 in the field of view. Interestingly, one of these ULXs was also pulsating at the time — which is something black holes just do not do. Thus, the source of this ULX, at least, was revealed to be not a black hole but an ultraluminous pulsar!

NuSTAR also helps measure the spin of black holes with observations of the X-ray iron absorption line. This again has to do with accretion: black holes with fast prograde spin (where the black hole and its accretion disk spin in the same direction) host an accretion disk that is very close to the hole itself, while non-spinning and retrograde-spinning black holes host accretion disks that are farther and farther away. These distances are reflected in the height of the iron absorption line which appears in the X-ray spectrum, making it visible to NuSTAR! However, such observations can become tricky when foreground effects come into play and blur the iron absorption line, meaning that it’s not always a foolproof measure of black hole spin.

Finally, Stern closed off with the possibility of observations closer to home. If theoretical particles called axions (incidentally, a great dark matter candidate!) exist, they could be transformed into X-ray photons when they encounter the magnetic fields of the solar corona. This is called the Primakoff effect, and NuSTAR is just the instrument to detect it.

Interview of Daniel Stern by Huei Sears
Live-tweeting of the session by Luna Zagorac

Editor’s Note: This week we’re at the virtual 238th AAS Meeting. Along with a team of authors from Astrobites, we will be writing updates on selected events at the meeting and posting each day. Follow along here or at astrobites.com. The usual posting schedule for AAS Nova will resume on June 14th.

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LAD Plenary Lecture: Origins of Astrochemical Complexity (by Luna Zagorac)

Astrochemical complexity and its origins is a topic that is just too — well, complex! — to cover in a single plenary. For this reason, Karin Öberg (Harvard University) began with a small amendment to the talk title: she focused on “(Icy) Origins of Astrochemical Complexity (During Planet Formation).” Specifically, she tracked the origins of volatile organic compounds through the process of planet and star formation. In chemistry speak, “volatile” means that these molecules prefer to be in the gas stage, while “organic” means that they necessarily have a carbon (C) atom, often linked to oxygen (O) and nitrogen (N). Understanding where these molecules come from is crucial, because they are the building blocks of life on Earth!

But before we can have life, we have to have a planet. The story of planet formation, roughly, is as follows: first, there is a cloud of dust; as this cloud collapses it forms a protostar in the center, and subsequently a protoplanetary disk around it. This system evolves until it begins to look something like our solar system: a central star with (some terrestrial) planets orbiting it, one of which might contain a life-form. But where along this celestial journey did we pick up enough organic volatile molecules to make up said life-form?

The answer: at every stage! First, consider the cloud stage: this is the only stage of the process cold enough (~10 K!) to form ices of volatiles such as methanol, CH3OH. Because these ices are also detected in the later protoplanetary disk, this must mean the ices survive into the next stage of the process! Furthermore, though it’s too cold to spontaneously turn these methane ices into more complicated compounds, lab experiments show that there are a few channels for getting these reactions started. One channel is an influx of energy from a stray cosmic ray, which would break up an icy molecule and send it over its activation potential for reacting with its neighbors; another has to do with oxygen insertion (see Jenny Bergner’s LAD Dissertation Talk Prize for more on this!). Once the protostar forms, it warms up its surroundings to about ~30 K, where not only is it easier to form complex molecules, but different mixtures become possible. All of these compounds are inherited by the protoplanetary disk, which in turn hosts its own in situ chemical reactions further contributing to molecular diversity and complexity.

The takeaway: not only are organic chemical environments of planet-forming regions shaped by cloud, protostellar, and in situ disk chemistry, they are also shaped by ice organic chemistry. For the latter, lab experiments have been and continue to be crucial in identifying new formation pathways and their efficiencies.

Interview of Karin Öberg by Ellis Avallone
Live-tweeting of the session by Luna Zagorac

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Press Conference: Molecules in Strange Places (by Tarini Konchady)

The first presentation at this briefing was given by Kate Gold (Bryn Mawr College) and Deborah Schmidt (Franklin & Marshall College). They discussed the preliminary results of a search for molecules around planetary nebulae (PNe). PNe play a key role in determining the chemical content of the interstellar medium, so it’s important to ascertain what molecules can survive the violent irradiation that occurs in the PNe stage. Models suggest that scarcely any molecules make it out intact, but observations point to the opposite being true! Using the 12 Meter Telescope and the Submillimeter Telescope in Arizona, the team searched for signatures of the molecules HCN and HCO+ in 13 PNe of varying ages. Not only did they find significant fractions of these molecules around most of the observed PNe, they also found that the presence of those molecules did not change significantly with PNe age.

The next presentation was given by Lucy Ziurys (University of Arizona) on using ALMA (Atacama Large Millimeter/submillimeter Array) to search for the previously mentioned molecules in other galaxies. Given that PNe are an end stage for some stars, they have a lot to tell us about stellar evolution. One open problem in astrophysics is how we get very non-spherical PNe from roughly spherical stars. With the relatively new discovery that PNe can be molecule-rich, researchers decided to try using ALMA to make “molecular images” of PNe by observing the molecular gas associated with these objects. These images offer a new window into PNe because the cold molecular gas produces features that don’t usually show up in optical images. These results could point us to how PNe are shaped.

The third presentation was given by Lilia Koelemay (University of Arizona) on the detection of organic molecules on the outer edges of the Milky Way. While our galaxy has some assumed habitable zone (the “galactic habitable zone”), organic molecules have been found much further out than the extent of that habitable zone. This motivated another search for organic molecules in molecular clouds at distances between ~42,000 light-years and ~77,000 light-years from the center of our galaxy. The search found that the abundances of the relevant organic molecules didn’t change much with distance — extending the “OZ” or organic zone of the Milky Way. This finding informs our ideas of where life could arise. Press release

The last presentation was given by Annie Hughes (Institut de Recherche en Astrophysique et Planétologie) on the PHANGS-ALMA (PHANGS: Physics at High Angular resolution in Nearby GalaxieS) survey of molecular gas across a large sample of galaxies. Molecular gas is critical to star formation and star formation influences galactic structure, so it follows that we could learn a lot by studying the distribution and properties of molecular gas in a large variety of galaxies. With this in mind, the PHANGS-ALMA survey mapped CO emission across 90 galaxies. With these observations, the team found that molecular clouds in the central regions of galaxies tended to be denser, more massive, and more turbulent than their counterparts on the outskirts. Press release

Live-tweeting of the session by Tarini Konchady
YouTube recording of the session on the AAS Press Office channel

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STScl Town Hall (by Sabina Sagynbayeva)

Dr. Nancy Levenson, the deputy director of STScI, reported on the status of the existing and upcoming missions and described new opportunities designed to advance astrophysics through the 2020s.

She started off reporting the most recent status of the institute: Most Institute staff are working from home now. More people will return on-site in the coming months, but STScI will not host visitors or conferences in person through the calendar year due to focus on current missions.

What missions? Here’s a status update on a few:

• JWST is going to launch later this year!
• Hubble’s doing great. Cycle 28 is underway, and the review for Cycle 29 will happen this month. STScI encourages you to share your results if you used Hubble or another telescope supported by STScI, and STScI can help disseminate newsworthy findings. Hubble’s program ULLYSES, a large Director’s Discretionary program for the community to obtain a spectroscopic reference sample of young low- and high-mass stars, put out its second data release in March 2021.
• The Nancy Grace Roman Telescope will provide a Hubble quality with 100 times the field of view. Roman is working toward launch in the mid-2020s. Also, the primary mirror is complete and all WFI science detectors are available. Levenson also reports that ALL data from Roman will be available with zero exclusive access period. Also, Mikulski Archive for Space Telescopes (MAST) can provide data from Hubble, Webb, Roman, Pan-STARRS, and others.

STScI user committees welcome your input! Their reports and contact information are available on the STScI.edu website:

• Space Telescope Users Committee (STUC)
• JWST Users Committee (JSTUC)
• MAST Users Group (MUG)
• Roman Space Telescope Advisory Committee (RSTAC)

Next, Christine Chen discussed the JWST Cycle 1 General Observer (GO) Program. Approximately 33.5% of successful proposals are led by PIs from ESA countries, and 4% by PIs from Canada, but overall there were proposals from all over the world. She also reminded us of the Dual Anonymous Review: proposal reviews were conducted with the identities of the proposal teams removed from the proposals, and each panel has a Leveler who helps to keep the panel discussion focused on the selection criteria.

Chen outlined some of the approved proposals:

• Protoplanetary disks observations will study the chemistry of water and organics in the terrestrial planet forming regions (<5 AU) and use coronagraphic imaging to search for protoplanets in at least 12 disks
• Transiting exoplanet observations include the study of sub-Neptunes and super-Earths with time-series spectroscopy and planets transiting active M dwarf stars.
• Nearby Galaxy Observations will contribute to understanding of the stellar populations and ISM within nearby galaxies
• AGN outflows and feedback observations will leverage 5–28 µm spectroscopy to determine the heating mechanisms for and estimate the energetics of outflows; characterize the molecular gas, dust, AGN, star formation and metallicity within the central regions; and map the AGN’s influence on the distribution of metals and star formation in different environments
• Galaxy imaging surveys will image the sky using NIRCam (and MIRI), providing the gold-standard imaging data set for galaxy assembly studies, studying the sources responsible for the reionization of hydrogen, and probing the era of the first galaxies, pushing beyond z = 10
• Galaxy spectroscopic surveys will observe thousands of galaxies using NIRCam and NIRISS WFSS to provide line diagnostics reaching redshifts up to z = 7 and beyond, enabling characterization of the physical properties of galaxies all the way to cosmic dawn

A final point mentioned is that STScI is hosting JWebbinars! These are entirely virtual classes with ~40 participants with hands-on instructions on common data analysis methods for JWST observations. All materials are made available after the classes.

Live-tweeting of the session by Sabina Sagynbayeva

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Meeting-in-a-Meeting: Transient Discovery with Machine Learning (by Sabina Sagynbayeva)

Gautham Narayan (University of Illinois at Urbana-Champaign) opened the session with “Deep Learning for Multimessenger Astrophysics.” How can we classify sources in the huge volume of photometric data expected in the future? Narayan presents on the Photometric LSST Astronomical Time-series Classification Challenge (PLAsTiCC), a means of using deep learning to classify the time-domain sky. The primary goal? To set up a massive time-domain simulation infrastructure and jumpstart machine learning photometric classification efforts.

Andrew Vanderburg (University of Wisconsin-Madison) next talked about “Exoplanet Detection using Machine Learning”. The problem in exoplanet detection is that planets are not the only things that cause stars to dim periodically! We have a lot of data from Kepler and TESS, but we need to identify the dimmings that are specifically caused by planets. Machine learning does two things better than humans: it can perform similar tasks much faster, and it can perform pattern recognition, identifying predictive relationships between different observations that are too complex for traditional methods to solve. Vanderburg presented on how these advantages have been leveraged for exoplanet detection with great success, resulting in multiple potential new planets and the first mass measurement of a known planet around an active star.

Michelle Lochner (University of the Western Cape/ South African Radio Astronomy Observatory) next discussed “Transient Classification and Anomaly Detection in the LSST Era.” The Vera Rubin Observatory will produce an incredible dataset, but it is also going to be an incredible challenge. There are rare events that we know exist, e.g. kilonovae, which Lochner calls “known unknowns.” But unknown unknowns are exciting, too! How do we discover new phenomena among 10 million possibilities? An interesting anomaly to one scientist isn’t interesting to another scientist — so here comes active learning. Lochner built Astronomaly, a package for active anomaly detection for astronomical data. By running machine learning algorithms, this pipeline picks up things that are strange and gives an image a score of how “interesting” it is. Lochner concluded by mentioning their mentoring program for women and gender minorities in physics (and they need more mentors!).

Ashish Mahabal (Caltech) talked about “Machine Learning Aided Classification of Transients and Variables in ZTF.” The Zwicky Transient Facility (ZTF) has a catalog of billions of astronomical objects and specialized filters depending on science use cases. It registers hundreds of thousands of events every night. Mahabal provided an overview of parts of the machine learning workflow in place to discover and classify transients by combining ZTF photometry and spectra from the SED Machine (SEDM).

Guillermo Cabrera-Vives (Department of Computer Science, University of Concepción) wrapped up with “Machine Learning within the ALeRCE System: Past, Present and Future”. ALeRCE is an astronomical alert broker — a system that ingests, processes, and redistributes alerts that come from programs like ZTF — or, in the future, LSST. ALeRCE receives an alert stream about possible transient detections, and then applies machine learning to classify the transient, crossmatch it with archival catalogs, and more.

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NSF Town Hall (by Macy Huston)

The NSF Town Hall began with updates on Division of Astronomical Sciences (AST) staffing from interim director Chris Smith, followed by updates on observatories and instruments. In recent NOIRLab news, the Dark Energy Survey’s first three years of observations have produced 30 new papers. Meanwhile, the Dark Energy Spectroscopic Instrument (DESI) has completed its trial and begun the five year survey. Exciting news at the Green Bank Observatory is the development of radar capabilities by the NRAO on the Green Bank Telescope.

Finally, the Covid-19 pandemic has caused delays and additional expenses in telescope construction. The Daniel K. Inouye Solar Telescope is now estimated to begin operations at the end of 2021. Its Cycle 1 call for proposals will be May 1, 2022, and the start of steady-state observations is anticipated for November 2022. The Vera C. Rubin Observatory is now estimated to begin operation in the first half of 2024.

James Neff reviewed the AST division’s programs and budgets. Two new programs for postdoctoral fellows (MPS-Ascend, NSF 21-573) and pre-tenure faculty (MPS-LEAPS, NSF 21-570) have deadlines approaching in mid-June. Funding opportunity deadlines and program leads were reviewed, and are available on their website.

Ashley Vanderley presented the status of the recently collapsed Arecibo Observatory. Cleanup, an environmental assessment, and an investigation of what went wrong are underway. The observatory team also prioritizes historical preservation, salvaging objects such as a receiver and some reflector panels for display at the site or a museum. The Arecibo Observatory Options Workshop is currently underway. Those who did not register in time are able to watch informational talk recordings on the website and submit ideas to Arecibo-feedback@nsf.gov.

The Electromagnetic Spectrum Management (ESM) exists to ensure the scientific community access to portions of the EM spectrum needed for research. This has been expanded from a focus on radio to include infrared and optical concerns, increasing the management team from 1–2 members to 3–4. Their astronomical concerns are keeping clean, wide bandwidths for radio astronomy, keeping dark skies in the optical/IR, and broadening participation.

Lastly, Chris Smith returned to present the NSF’s fiscal year 2022 budget request. The request increased from $8.5B in FY2021 to $10.17B. Their goals prioritize fundamental research, emerging technology, equity, climate science and sustainability, and research infrastructure. They are looking forward to the Astro2020 community recommendations to help guide upcoming year budgets. They will examine science priorities, the required facilities, and how to support a diverse pool of science-engaged people.

Live-tweeting of the session by Macy Huston

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Annie Jump Cannon Prize Lecture: Turbulent Beginnings: A Predictive Theory of Star Formation in the Interstellar Medium (by Ellis Avallone)

The first afternoon plenary of AAS 238 Day 2 is by Blakesley Burkhart (Rutgers University), winner of the 2019 Annie Jump Cannon Prize! Dr. Burkhart is an expert in turbulence, a complex phenomenon that affects space at a vast range of scales.

Her talk begins by first highlighting Annie Jump Cannon herself, whose work in the early 20th century set the stage for the now well-established subfield of stellar evolution. Star formation, however, is an astrophysical process that remains largely unsolved. According to Dr. Burkhart, “We really don’t have a good predictive model [for star formation].” Uncertainties in star formation processes, incidentally, reverberate through all aspects of astrophysics, from galaxy dynamics to planet formation.

Next, Dr. Burkhart describes a key question that threads through star formation research: the star formation efficiency problem. If we assume gravity is the only factor that causes gas in the interstellar medium to collapse into stars, we should observe a star formation rate around 250 solar masses per year. However, if we look at our own galaxy, we observe a star formation rate around 3 solar masses per year. This makes one thing abundantly clear: star formation is incredibly inefficient! Our key problem is now focused on not forming stars, i.e., preventing star formation from being too efficient in our models.

Dr. Burkhard notes that when we look at star formation observationally, we find that star formation efficiency rate is around 1% for both close-by and high redshift galaxies. These similarities from such a diverse galaxy sample indicate that there’s something universal about the physics in star-forming clouds. With that, Dr. Burkhart describes the analytical models and simulations that are critical for understanding this problem.

Most analytical models use a lognormal distribution to describe the density of gas in star-forming clouds. This distribution offers a straightforward way to compute properties of a star-forming cloud — like the star formation rate. However, when we look at observations, we find that parameters that we expect to be correlated with one another are not correlated at all. Therefore, the model has to be adjusted! Dr. Burkhart and her group looked to simulations to determine how to adjust the model and found that at high densities, the gas density distribution behaves much more like a power law. They additionally found that the power law distribution agreed much more strongly with observations.

Simulations are also incredibly useful for looking at which physical processes suppress star formation. Dr. Burkhart’s group found that turbulence does not provide support against gravitational collapse in a star-forming cloud, which was quite the surprise! Instead, magnetic fields and feedback from young stars are the processes that prevent the cloud from collapsing efficiently, and therefore do all the heavy lifting against gravity. When they incorporate these factors into their analytical model, they are able to reproduce the star formation efficiency rate and gas depletion time expected in simulations, which bodes well for future comparisons with observations.

Interview of Blakesley Burkhart by Pratik Gandhi
Live-tweeting of the session by Ellis Avallone

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Meeting-in-a-Meeting: Measuring the Properties of Stars with Machine Learning (by Mia de los Reyes)

In this session of the “Machine Learning in Astronomy” splinter meeting, we learned about some of the ways data-driven techniques can be used to study stars!

Stella Offner (The University of Texas at Austin) started us off by speaking about “Harnessing Machine Learning to Identify Stellar Feedback.” Stars are messy! They inject energy and momentum into their environments, and this feedback can produce all kinds of features in the interstellar medium. Such features, like bubbles and outflows, are often identified visually — but this is time-consuming, subjective, and hard! Offner described an algorithm that instead uses convolutional neural networks to identify these features. After being trained on simulated maps of molecular emission, this algorithm does a great job of finding structures produced by feedback — it’s even been able to show that the feedback in these features scales almost one-to-one with the number of individual young stars in a molecular cloud!

Next, Anna-Christina Eilers (MIT) discussed “Mapping the Milky Way with data-driven models.” We live in an era of abundant information about the positions, motions, and spectra of stars in the Milky Way, which can be used to answer open questions about our galaxy’s formation and evolution. But these data have uncertainties! Eilers is using machine learning techniques to derive precise distances and to calibrate stellar abundances. For example, by assuming that red giant branch stars have “standardizable” luminosities, Eilers can use photometric and spectroscopic data to predict their distances with high precision. Similarly, stellar abundances can be predicted using a function of stellar properties. These can be used to make precise maps of stellar velocities and abundances in the Milky Way.

Melissa Ness (Columbia University) went more in-depth on stellar abundances with a talk on “Measuring the properties of stars with data-driven computational approaches.” Surveys like APOGEE and LAMOST are providing us with millions of stellar spectra. What information is contained in these spectra, and how can we use them for science? Ness describes how pipelines like The Cannon are able to reproduce stellar spectra with a simple model that includes only a few stellar properties, like effective temperature, surface gravity, and iron abundance. Interestingly, although spectra contain information about many elements, just a few elements (like iron and magnesium) are needed to predict the abundances of other elements. Finally, data-driven techniques can be used to identify stars with outlier spectra, which can help probe the physics of stellar evolution.

Lily Zhao (Yale University) also discussed stellar spectra, but focused more on measuring radial velocities rather than abundances. In the talk “Machine Learning for Extreme Precision Radial Velocity,” Zhao explained that in order to discover an Earth-like planet using radial velocities, we’d need a spectrograph with around 10 cm/s precision. Next-generation spectrographs can reach sub-m/s precision, but spectroscopic effects from stellar activity become a significant source of error. This is where machine learning comes in! Data-driven techniques can effectively reduce the impact of stellar activity on radial velocity measurements.

Last but not least, J. Ted Mackereth (CITA / Dunlap Institute / University of Toronto) spoke about “The Stellar Age Revolution, feat. Asteroseismology, Spectroscopy, and Machine Learning.” One of the most precise ways to measure stellar ages is by using asteroseismology, which is classically done by measuring the global properties of stellar oscillations. We can do even better if we use more detailed information about individual frequencies, or if we use additional information from spectroscopy! Again, data-driven techniques can help with this. For example, using combined data from APOGEE abundances and Kepler asteroseismic data, a neural network can significantly improve upon uncertainties in stellar ages. With these more precise measurements, we can start to pick out patterns of ages, dynamics, and abundances in the Milky Way.

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LAD Laboratory Astrophysics Prize: Tales from a Life in Laboratory and Observational Molecular Astrophysics (by Luna Zagorac)

The winner of the AAS LAD Laboratory Astrophysics Prize, Geoffrey Blake (Caltech), looked back on a long career of astrochemical achievements in his talk. The Blake group at Caltech focuses on spectroscopy, spanning the range from microwave to infrared and near-optical frequencies. This is equivalent to a range in temperatures from a few to a few thousand Kelvin, allowing them to probe a wide variety of molecular motions in the sky. Blake emphasized the exquisite quality of ALMA data for astrochemistry, noting that his group worked on laboratory instrumentation to bring it in step with the quality and quantity of observational data. On the other hand, the opposite is true when studying chiral molecules with three dipole moments: they are very-well understood in the lab, but they would require circularly polarized light sources in the sky imaged with an instrument at least the size of the Square Kilometre Array to study observationally. Finally, he highlighted how Spitzer data allows us to study ices and gases (including water!) in planetary formation contexts. He closed out his talk with acknowledgements of both his mentors and past and current students and postdocs, noting particularly how lucky he was to become a Duke Microwaver during his time at Duke University, which ultimately led him to discovering his own astrochemical path.

Live-tweeting of the session by Luna Zagorac

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LAD Dissertation Prize: Oxygen Insertion Chemistry: A Low-temperature Channel to Organic Molecule Production (by Luna Zagorac)

The graduate thesis written by Jenny Bergner (University of Chicago) was instrumental in the discovery of a new pathway for complex molecules to form in the icy interstellar medium (ISM): it’s no wonder that she won the LAD Dissertation Prize! Recreating the conditions of the ISM in the lab (a temperature of about 10 K and pressure many orders of magnitude below atmospheric), Bergner was able to use infrared spectroscopy to monitor what happened to icy molecules under these conditions. Turns out, an oxygen singlet state (a form of oxygen atom denoted as O(1D)) is able to insert itself directly into the bond between a carbon and hydrogen atom, forming new organic compounds in a process called O-insertion. The kicker? It’s able to do this without any energy input — meaning, it could even happen in the harsh conditions of the ISM!

This process leads to fragmentation, meaning that new but less complex molecules are produced. However, this is true of so-called saturated hydrocarbons, with a single bond between the C and H atom. In unsaturated hydrocarbons, which might have double or triple bonds between two carbon atoms, an analogous process called O-addition can take place, again with no energy input. Thus, O-insertion and O-addition are able to account for much of the astrochemical complexity seen in ISM ice. Furthermore, no other mechanism can explain the production of ethylene oxide (which has been detected in the ISM). Finally, Berger talked briefly about the role of comets in transferring ISM ices into protoplanetary systems. Small grains could not survive this journey, but larger ones were found to experience virtually no loss on this journey.

Interview of Jenny Bergner by Luna Zagorac
Live-tweeting of the session by Luna Zagorac

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SPD Harvey Prize Lecture: A Journey from Quiet Sun Magnetic Fields to Flares (by Sabina Sagynbayeva)

The SPD/AAS early career Karen Harvey Prize is awarded in recognition of a significant contribution to the study of the Sun early in a person’s professional career. This year’s winner, Lucia Kleint (University of Geneva), got into research on solar flares accidentally, but she continues to investigate their inner workings today while also trying to understand how to improve solar observations! 

Solar flares are powered by strong magnetic fields; an incredibly useful tool for studying these magnetic fields is polarimetry, a method where polarization of spectral lines are used to reconstruct solar magnetic fields. Dr. Kleint’s PhD focused on the variation of the turbulent magnetic field over the course of a solar cycle. However, they found that polarization gets canceled out due to the sum between positive polarity and negative polarity. But at the Sun’s limb, the polarization is not zero. That’s why they position the spectrograph very close to the limb (5’’ from the limb). In simulations, they can see that the polarization is decreasing. The Hanle effect (depolarization depending on the magnetic field) can help to detect even small magnetic fields. They measured the magnetic field every month and found no variation, a surprising constant from 2007–2010!

Why does the turbulent magnetic field depend so much on the spectral line it’s observed with? Maybe these spectral lines show different things! We need separate images of the Hanle effect, but so far it’s not possible. They are still unable to properly resolve small-scale magnetic fields due to a lack of photons. Here is where DKIST comes in: this behemoth of a solar telescope is able to look at fine scales on the solar surface using multiple spectral lines.

Dr. Kleint continues to look at solar flares today. People have a general idea how solar flares work, but we still have a hard time predicting them. Dr. Kleint is particularly interested in how to predict solar flares, understanding how their energy is dissipated and the evolution of their magnetic structure, and why other sun-like stars produce much stronger flares than what we observe on the Sun.

When solar flares were first observed, interpreting these observations was extremely difficult.  Today, dedicated flare campaigns at numerous observatories around the world have yielded an overabundance of data. One such flare campaign at the Dunn Solar Telescope has observed what NASA has called the best-observed flare, which sparked the authorship of dozens of papers analyzing this single event!

Even with this abundance of flare observations, puzzling things kept showing up in the observations. Observations from the Solar Dynamics Observatory HMI instrument prompted the adoption of a new flare mode. However, the difference in activity between the solar surface and atmosphere at the flare site leaves more questions unanswered. So the question is: Are our models valid for all flares, or only for particular flares? Machine learning has been critical for digging through the mountains of flare observations, however Dr. Kleint wants to know how we can improve instrumentation to address these unanswered questions. 

Her wish list:

• So far, we have no regular high-resolution chromospheric magnetic field measurements. Do we need DKIST, or a spacecraft?
• Advances in flare modeling and analysis (Radyn, RH, STIC, machine learning)
• Automatic analysis of millions of spectra/images, which may enable flare prediction

The observations wouldn’t be possible without telescopes! Dr. Kleint discussed the recent redesign of the GREGOR solar telescope, located in Spain. The improvements included a new mirror, producing higher contrast; a new optics design, which solved image aberrations; and reduction of vibrations and temperature variations.

There are still many open questions from quiet Sun magnetic fields to flares that are waiting to be explored.

Live-tweeting of the session by Sabina Sagynbayeva

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Seminar for Science Writers: Get Ready for Webb! (by Tarini Konchady)

Christine Pulliam and Hannah Braun (Space Telescope Science Institute) introduced this seminar, which is intended to give an overview of the James Webb Space Telescope (JWST) and the science it will do. First, Eric Smith (NASA Headquarters) provided a description of the final months before JWST’s expected launch and the commissioning that will follow. The telescope continues to be tested to ensure it will work after launch, and the Cycle 1 observing programs have been announced (see the summary of the STScI town hall). Following launch, JWST will see a roughly 180-day commissioning, during which it will ready itself to observe. This process includes the deployment of the telescope mirrors and the calibration of the scientific instruments on board. Cooling is also a critical part of this process, since JWST will be observing in the infrared.

The following speakers focused on the science that will be done by JWST. Dan Coe (Space Telescope Science Institute) discussed how the telescope will allow us to view the oldest galaxies yet — in fact, it will put us in reach of the first galaxies to have formed in the universe. This part of JWST’s mission will include observing the Hubble Ultra Deep Field. One interesting note is that the faintest galaxies JWST will be able to see can be observed in two ways: by staring into seemingly empty patches of sky for a very long time, or by identifying lensing systems. Spectra of these distant galaxies will also be extremely valuable, as they can tell us about the composition of those galaxies.

Next, Ilse Cleeves (University of Virginia) discussed JWST’s potential impact on the study of planet and star formation. Specifically, astronomers are very interested in how formation happens and the chemical composition of the resulting stars and planets. Right now, ALMA has been our best probe of star and planet formation, and its high quality observations have opened many avenues for JWST to explore. These avenues include observing the earliest stages of star formation, characterizing the composition of cold interstellar medium, and constraining the sort of material that forms terrestrial planets.

Knicole Colón (NASA Goddard Space Flight Center) followed with an overview of the exoplanet science that can be done with JWST. Aside from the previously mentioned formation questions, JWST will also be able to study the compositions of exoplanets and their atmospheres. The telescope’s strength here lies in its infrared capabilities; direct imaging of exoplanets will be more viable than it has been before, and a wider range of chemical signatures will be detectable in transiting exoplanets’ atmospheres. JWST will also afford us detailed study into the disks that form planetary systems.

Finally, Heidi Hammel (Associated Universities for Research in Astronomy) covered the solar system science planned with JWST. Given JWST’s observing position, it will not be able to observe much interior to the Earth’s orbit. However, that still leaves a lot to explore! JWST will be able to create surface maps of Mars, tracing dust, water, and other material. It will also be able to explore the diversity in asteroids and comets. The gas giant planets also have a lot to reveal, from why Jupiter’s Red Spot is red to the weather on Uranus. Planetary moons that appear to have water, like Europa and Enceladus, will also be studied. The even more distant Kuiper belt objects will be within JWST’s reach, and the telescope is also ready for unexpected events like the 1994 Jupiter impact.

More information can be found at https://webbtelescope.org/ and https://webbtelescope.org/news/webb-science-writers-guide.

Live-tweeting of the session by Macy Huston
YouTube recording of the session on the AAS Press Office channel

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Plenary Lecture: Our Galaxy in Context: Satellite Galaxies around the Milky Way and Its Siblings (by Mia de los Reyes)

Marla Geha (Yale University) wrapped up Day 2 of #AAS238 by discussing the “nieces, nephews, and niblings” of the Milky Way: the low-mass satellite galaxies around Milky Way-like galaxies! Why focus on these small galaxies? The ~60 known satellite galaxies around the Milky Way are useful laboratories for testing theories about cosmology and galaxy formation.

From a cosmological standpoint, these galaxies can help us probe the nature of dark matter! One extreme example: “cold” (i.e., non-relativistic) dark matter simulations predict lots of low-mass galaxies (galaxies with stellar masses < 106 solar masses), while “warm” dark matter models predict far fewer of them. Satellite galaxies can also answer questions about galaxy formation and evolution — in particular, what processes turn off (“quench”) star formation in galaxies? Nearly all of the satellites close to the Milky Way have been quenched, while low-mass galaxies further away still have gas and are still able to form stars. Is this “quenching fraction” characteristic of all galaxies that are satellites of more massive galaxies, or is the environment around our Milky Way somehow unique?

In order to make quantitative comparisons between satellite galaxy populations, we need to observe approximately 100 Milky Way-like galaxies. This is where the Satellites Around Galactic Analogs (SAGA) survey comes in! The SAGA survey has so far identified around 40 Milky Way-like galaxies, and many of their satellites look very similar to the Milky Way’s satellites. Overall, the numbers and luminosities of satellite galaxies around Milky Way-like hosts are consistent with what we see in the Milky Way, and with predictions from simulations. But the quenched fractions of satellite galaxies seem much lower than we expect from our galaxy and from simulations! Hopefully more data will help us figure out what’s going on — and maybe soon we’ll be able to study more low-mass galaxies in general, not just ones around Milky Way-like galaxies!

Interview of Marla Geha by Mia de los Reyes
Live-tweeting of the session by Mia de los Reyes

Editor’s Note: This week we’re at the virtual 238th AAS Meeting. Along with a team of authors from Astrobites, we will be writing updates on selected events at the meeting and posting each day. Follow along here or at astrobites.com. The usual posting schedule for AAS Nova will resume on June 14th.

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Welcome Address (by Luna Zagorac)

The 238th Meeting of the American Astronomical Society was opened by President Paula Szkody, who acknowledged that the meeting was originally scheduled to take place in Anchorage, Alaska. While Dr. Szkody acknowledged many people are missing the in-person interactions of AAS meetings, meeting online has allowed more folks to join the summer meetings that would be possible in-person. Dr. Szkody led us through AAS officer and staff changes, progress of AAS publications, changes to prize nomination processes, and more. Finally, Dr. Szkody gave us a quick overview of the schedule of the meeting, and highlighted that another pro of meeting online is the ability to go back and watch overlapping talks. Read on for summaries of the plenaries and press conferences of Day 1 of #AAS238!

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Fred Kavli Plenary Lecture: A New Era of Measuring Magnetic Fields in Galaxies (by Mia de los Reyes)

Astronomers like to joke that a classic question to ask after any colloquium is: “What about magnetic fields?” For a very long time, magnetic fields have been easy to “hand-wave” away because we honestly haven’t known much about them. But that’s starting to change, even in complex systems like galaxies. As Enrique López Rodríguez (Stanford Kavli Institute for Particle Astrophysics and Cosmology) points out, we’re finally starting to put together a “complete picture of galaxy evolution from a hydromagnetic framework.”

This is in part due to the impressive efforts of facilities like the Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA can observe magnetic fields by measuring the polarization of light in far-infrared wavelengths. This polarization is caused when dust grains align along magnetic field lines; light scattered by the aligned dust grains then gets polarized. Using this technique, Dr. López Rodríguez and his collaborators have been able to produce beautiful maps showing magnetic field strength and structure around nearby galaxies. From these maps, we’ve been able to determine that in spiral galaxies, large-scale magnetic fields tend to be ordered and follow the spiral arms. However, small-scale dynamo processes (like turbulence from star formation or galaxy interactions) can make the magnetic field more chaotic on local scales. Other phenomena might also affect galactic magnetic fields — for example, strong outflows caused by extreme starbursts can drag a galaxy’s magnetic field away from the galactic plane!

These are exciting first steps towards a deeper understanding of how magnetic fields contribute to galaxy evolution. Hopefully new observations (from facilities like SOFIA, and potentially even future telescopes like the proposed Origins Space Telescope) will help us continue to understand how magnetic fields work on all scales.

Interview of Enrique López Rodríguez by Luna Zagorac
Live-tweeting of the session by Mia de los Reyes

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Press Conference: Stars & Clusters (by Macy Huston)

The first press conference presentation of AAS 238 was given by James Schroeder (Wheaton College, Illinois) & Gregory Howes (University of Iowa), who explored the connection between aurorae and Alfvén waves. Aurorae are caused by disturbances in Earth’s magnetic field which accelerates charged particles. These, in turn, perturb atmospheric particles, emitting the beautiful design we often call the northern lights. Alfvén waves are a type of disturbance in magnetic fields where ions oscillate on magnetic field lines, and they have been detected during auroral events. The team used the Large Plasma Device to produce Alfvén waves in a lab, and found that electrons moving at nearly the speed of the waves would “surf” them and be accelerated. So, Alfvén waves can cause the acceleration of electrons which causes aurorae! Press release

Next, Emily Mason (USRA & NASA Goddard SFC) discussed the jet/coronal mass ejection continuum. Solar eruptions seem to exist on a spectrum, but we are most familiar with jets (small-scale ejections of plasma from a star) and coronal mass ejections (significant expulsions of plasma and magnetic fields from a star). The 2016/03/13 solar event appears to be the missing link between these two categories. In the observations, we see a “failed eruption” that collapses before material exits the Sun. The mechanism behind this event is not yet fully understood, and magnetohydrodynamic simulations are underway. Press release

Peter Garnavich (University of Notre Dame) presented the second known propeller cataclysmic variable, J0240. A cataclysmic variable star (CV) is a white dwarf (WD) star that varies in brightness over time as it accretes mass from a red “donor” star. A unique category of these is the “propeller” CV, in which the WD’s rapid rotation and magnetic field cause a significant amount of the gas pouring off the donor to be ejected from the system. The first of these found was AE Aquarii, and J0240 is the second. It is the first that has been visibly eclipsing. The measurements show a spiral pattern in the gas ejection, recurring fast flares, and absorption lines directly showing the gas. The system likely formed when a period of unstable mass transfer increased the WD’s rotational speed. As this rotational energy is used to eject gas, the WD will slow again, returning to a normal CV state. So, the propeller CV is likely a short-lived evolutionary phase that can happen in CV systems. Press release

Kris Davidson (University of Minnesota) presented Eta Carinae’s evolution over time as a “supernova imposter.” Supernova (SN) imposters, or giant eruptions, look like SN explosions, but their stars somehow survive. While several of these have been seen, Eta Carinae is the only one near enough to study in detail. It was one of the brightest stars in the sky in the mid-1800s and ejected 10–20% of its mass. Stars undergoing this process are expected to return to their normal states in ~40 years, but Eta Carinae has been weird for almost 200 years. It was discovered that the star has a hot but smaller companion star, and the pair’s colliding winds make the recovery process unsteady. The star has become brighter than its nebula and is expected to eventually ionize its nebula, dramatically altering its appearance and properties. 

Lastly, Luke Bouma (Princeton University) presented the discovery that NGC 2516, an open cluster thought to extend about 30 light-years, has a surrounding halo which extends to 1,500 light-years. Stars form in clusters, where many get ejected, while the densest regions hold together longer as open clusters. NGC 2516 was thought to be a typical 30 light-year open cluster, but recent Gaia observations suggested that a halo of stars around it are spatially nearby and possibly evolutionarily connected, though different teams reached different conclusions about this. In a new study, scientists followed up with observations from TESS, measuring rotation periods from the stars’ light curves. Using these periods to estimate age (gyrochronology), the team found that the cluster’s core and surrounding halo are the same age, confirming that they formed together. This discovery about NGC 2516 leads to the question of how many other open clusters may actually be larger than we thought. Press release

YouTube recording of the session on the AAS Press Office channel
Live-tweeting of the session by Macy Huston

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NASA Town Hall (by Sabina Sagynbayeva)

Paul Hertz, the Director of the Astrophysics Division in the Science Mission Directorate (SMD) at NASA, told us about the present and the future of NASA’s missions. He started off by reminding us of one of the most exciting accomplishments of 2021: the landing of Perseverance! He also reminded us of other major accomplishments: Parker Solar Probe’s images are the first to show the planet’s dust ring for nearly its entire 360-degree span around the Sun; Fermi’s Gamma-ray Burst Monitor detected a short outburst of gamma rays; Fermi’s Large Area Telescope detected GeV photons within minutes of the outburst. 

One of the important missions of the future is the launch of the James Webb Space Telescope. The launch is scheduled for October 2021, and so far all observatory deployments were successfully completed and Cycle 1 observing programs were selected. There’ll be a special session on Webb Space Telescope on Wednesday: Session 305. We also should expect a complete Nancy Grace Roman Space Telescope by the end of 2021!

There are a lot of exciting scientific projects that are coming in the near future, but today Hertz also emphasized DEI, and what NASA does to achieve inclusive and diverse teams. He also spent some time talking about how COVID-19 affected NASA’s missions and also what they have accomplished during the pandemic. So let’s dig into these two topics. 

NASA is creating a multi-pronged approach to achieve diversity and inclusion. One example is their web page with NASA-provided wellness resources for its researchers to better maintain a work-life balance. NASA also encourages all interested members of the public to collaborate on citizen science projects. Moreover, Dual-Anonymous Peer Review (DAPR) has been successful in removing some implicit bias towards women scientists, and according to a questionnaire DAPR improved the overall quality of the peer review. NASA is also developing a policy to ensure that the results of its federally funded scientific research are shared openly.   

NASA has been in a mandatory telework configuration due to COVID-19 for over one year now. NASA Centers are planning for ramping up onsite activities when the 25% occupancy limit is lifted. SMD is working toward multiple launches scheduled for the fall and winter of this year, including Webb, Lucy, Landsat-9, DART, IXPE, and GOES-T. Hertz also mentioned that government-wide rules allowed the flexibility to continue to pay salaries on a case-by-case basis for researchers, even if they couldn’t work during COVID-19. 

The NASA budget for fiscal year 2022 will help NASA accomplish its main goals, such as building the Earth Systems Observatory to enhance and integrate Earth system science and applications to increase the nation’s preparation, mitigation, and resilience in the face of climate change. It also keeps NASA on the path to land the first woman and the first person of color on the Moon and supports NASA efforts to strengthen inclusion, diversity, equity, and accessibility both within NASA and among the space community.

Finally, Hertz is stepping down from his position in 6 months but he emphasizes that he has accomplished all his goals. But the message he wants us to hear is: “[Looking at all these future missions], it’s a great time to be an astrophysicist!”

Live-tweeting of the session by Sabina Sagynbayeva.

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Plenary Lecture: The Time Is Now: Findings from TEAM-UP Report to Increase the Number of African Americans with Bachelor’s Degree in Physics and Astronomy (by Ellis Avallone)

The first afternoon plenary on day 1 of AAS 238 is all about the findings and lessons learned from the American Institute of Physics (AIP) TEAM-UP report! We covered the release of the report back at AAS 235 in January 2020, where we learned about the factors that lead to African American undergraduate student success in physics and astronomy departments. Tabbetha A. Dobbins (Rowan University), one of the founding members of the TEAM-UP task force, described the formation of the task force and what lessons were learned from it. 

The majority of the talk was focused on the 5 factors that TEAM-UP found were essential to African American student success: a sense of belonging, physics identity, academic support, personal support, and supportive leadership and structures. Dr. Dobbins also emphasized the importance of viewing students holistically, not just as students but as whole people with intersecting social identities and experiences. With these 5 factors in mind, Dr. Dobbins moved on to discussing recommendations for departments outlined in the report. 

She prefaced the discussion on departmental recommendations by introducing a case study. In the case study, a junior professor is looking to help a Black student who is struggling and isolated. However, the junior professor is unsure of how to help. Dr. Dobbins then described the recommendations made by the report. A key point: these suggestions purposefully do not include recommendations for students, but rather focus entirely on fixing the environments so that minoritized students can thrive. 

In the context of the case study, the first recommendation involves creating a culture where everyone is welcomed (i.e. having common spaces within the department, inviting speakers who can discuss the development of a student’s physics identity, and developing informal mentoring relationships). The department should also provide incentives for faculty to support minoritized students, both financially and as mentors; the report found that students who work as teaching or learning assistants are more likely to develop a sense of belonging and physics identity. 

To learn more about what you can implement in your department, check out the full report and follow the TEAM-UP task force for updates on the important work they continue to do!

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Press Conference: Black Holes & Active Galactic Nuclei (by Susanna Kohler)

For the second press conference of AAS 238, we turned to the ever-mysterious topic of black holes and their host galaxies. 

Alexia Lopez (Jeremiah Horrocks Institute, U. of Central Lancashire) opened the briefing with a recent unexpected find: an enormous arc of galaxies spanning a stunning 3.3 billion light-years across the sky. Such large-scale structures in the universe aren’t expected under the cosmological principle, an underlying tenet in the standard model of our universe that states that matter should be distributed homogeneously and isotropically on large scales. Press release

What happens to the active nuclei of galaxies (AGN) — accreting supermassive black holes — as they age? We may now have front-row seats to find out, according to Kohei Ichikawa (Tohoku University)! New multiwavelength observations of the heart of Arp 187 show some expected AGN features, like the presence of large-scale jets, but others are missing, like a central radio core. Ichikawa and collaborators have concluded that Arp 187 represents a “dying AGN” — the nucleus has already shut off, and we’re now seeing only the large-scale relics of its past activity.

Next up, W. Niel Brandt & Qingling Ni (Pennsylvania State University) introduced us to a new survey, XMM-Spitzer Extragalactic Representative Volume Survey (XMM-SERVS). XMM-SERVS is providing a unique X-ray look at the sky that fills the gap between deep surveys that cover small fields (<1 deg2) and shallow, wide-field surveys (tens or hundreds of deg2). In particular, XMM-SERVS provides X-ray coverage of three so-called Deep-Drilling Fields of the upcoming Rubin Observatory’s Legacy Survey of Space and Time (LSST) — fields of 10 deg2 that Rubin will observe much more often than the rest of the sky. XMM-SERVS has cataloged 12,000 X-ray sources in these fields, providing valuable context for LSST and a powerful view of growing supermassive black holes in a wide range of cosmic environments. Press release

Few events are more dramatic than the merger of two galaxies containing supermassive black holes at their centers — but Jonathan Williams (National Science Foundation & University of Maryland) is ready to top that with new observations of a triple merger of galaxies. In the source 2MASX J1631, two galaxies hosting AGN appear to be in the process of merging, and a third galaxy — possibly a dwarf galaxy that has already passed through the other two — lies nearby, tied to the pair via a tidal stream. Scientists are using this system to tackle fundamental questions about why galaxy cores turn on and off, and how merging galaxies evolve over time. Press release

In May 2019, LIGO detected the collision of two monster black holes of ~66 and ~85 solar masses in an event called GW190521. This raised eyebrows, as it’s believed that black holes of ~50–120 solar masses shouldn’t be able to form; stars the right size to form these black holes are thought to explode in something called a pair instability supernova. In our final briefing today, Jorick Vink (Armagh Observatory and Planetarium) introduced a possible explanation for this paradox: if a supergiant star evolves in a very low-metallicity environment, its disk winds would be very weak, preventing it from losing a lot of mass and entering the unstable size range. Such a star could successfully collapse into a black hole like the ones witnessed in GW190521 without first blowing itself apart.

YouTube recording of the session on the AAS Press Office channel
Live-tweeting of the session by Luna Zagorac

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Newton Lacy Pierce Prize Lecture: Stargazing and Supergiants: Betelgeuse, Dying Stars, and the Observational Future of Stellar Astrophysics (by Mia de los Reyes)

About a year ago, Betelgeuse became the subject of national attention when it dimmed dramatically, sparking questions about whether it was about to explode. Betelgeuse seems to be back to its normal brightness now (although you can check here for daily updates if you’re worried), and Emily Levesque (University of Washington) assures us that it’s (probably) not going to explode anytime soon. Levesque, the winner of this year’s Newton Lacy Pierce Prize for outstanding research in observational astronomy, finished off the first day of #AAS238 with a brief review of some of the science we’ve learned just from this one fascinating object.

High-resolution images of Betelgeuse show that its Great Dimming in late 2019 only affected its lower hemisphere. If Betelgeuse isn’t about to explode, what could have caused this dimming? First, convection may have produced a “cold spot” on Betelgeuse’s southern hemisphere, making it look dimmer… but there’s some disagreement about how much Betelgeuse’s temperature actually changed in 2019, and whether it was enough to cause the observed change in brightness. Alternatively, the Great Dimming could just be a “normal” variation in brightness, caused by pulsations or binary interactions that aren’t unusual for red supergiants like Betelgeuse. The final — and perhaps the most convincing — explanation is dust. Red supergiants eject lots of mass, which produces large dust grains that can block some of the light from a star.

Even if this particular star doesn’t explode in our lifetimes, we still want to know what happens to red supergiants right before they die. To fully understand what happens when the most massive stars in the universe go boom, we’ll need more observations of red supergiants near and far — including Betelgeuse. Fortunately, as Levesque emphasized, complementary observations from upcoming space telescopes and ground-based observatories will help us learn more!

Interview of Emily Levesque by Huei Sears
Live-tweeting of the session by Mia de los Reyes

This week, AAS Nova and Astrobites are attending the virtual American Astronomical Society (AAS) summer meeting.

AAS Nova Editor Susanna Kohler and AAS Media Fellow Tarini Konchady will join Astrobites Media Intern Luna Zagorac and Astrobiters Mia de los Reyes, Ellis Avallone, Sabina Sagynbayeva, and Macy Huston to live-blog the meeting for all those who aren’t attending or can’t make all the sessions they’d like. We plan to cover all of the plenaries and press conferences, so follow along here on aasnova.org or on astrobites.org!

Where can you find us? We’ll be at the Astrobites booth in the Grad Student Fair all week — stop by and join us in the chat room! In addition, you can catch Susanna, Tarini, and Luna at the press conferences all week.

We’ll also be hosting a short webinar on Wednesday at 5pm ET at the Astrobites booth, discussing how you can use Astrobites and/or get involved.

While we wish we could talk with you all in person, we’re glad to have this virtual alternative! We look forward to seeing you in sessions and visiting your posters throughout the next three days.

Lastly, if you’re interested in reading up on some of the keynote speakers before their talks at the meeting, be sure to check out the interviews conducted by Astrobites authors! They’ll be published throughout this week, and they provide a great opportunity to discover more about these prominent astrophysicists and learn about the paths they took to where they are today.

You can read the currently published AAS 238 keynote speaker interviews here. Be sure to check back all week as the remainder are released!

Will you be joining us online for the 238th American Astronomical Society meeting? AAS Publishing looks forward to seeing you there! You can come find us at the AAS Publishing booth in the virtual exhibit hall, and you can check out AAS-Publishing-related endeavors in a number of events throughout the week (some already underway!). Below are just a few.

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Making the Most of AAS WorldWide Telescope

Friday, 4 June, 11:00 – 12:30 pm (ET)

AAS WorldWide Telescope (WWT) is a free and open-source data visualization tool that runs right in your web browser. Use WWT inside Jupyter to explore imagery and data tables on the sky, or embed it on other websites to share your data with your colleagues, students, and the general public in a slick, intuitive interface. This interactive tutorial will introduce attendees to the WWT tool and its software ecosystem in the context of its applications to research, education, and broader impacts.

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Astronomical Data Visualization in the Age of Science Platforms

Session 1: Monday, June 7, 12:00 – 1:30 pm (ET)
Session 2: Monday, June 7, 4:10 – 5:40 pm (ET)

Astronomy is on the cusp of a major transition: simulations and modern surveys like LSST are starting to generate datasets far too large for individual researchers to download and analyze. Instead, researchers will need to bring their analysis to the data. This necessity has led virtually all major astronomical data centers to plan “science platforms” for remote research, generally centered on the web-based JupyterLab environment. This transition has enormous implications for the basic act of “looking at the data”. The classic astronomical data visualization tools are graphical applications that operate on local datasets. The age of the science platform demands tools built for a completely different paradigm: web-native applications that can provide a smooth user experience even while the actual data are stored in a distant archive. While the shift to this new paradigm presents a great deal of opportunity ­— the modern web is an extremely sophisticated development platform — it is also highly disruptive. What is the “state of the art” in web-native astronomical data visualization tools? What are the most important unmet dataviz needs of the new science platforms? Which researcher workflows can be preserved and which must be reworked? This splinter meeting will gather survey scientists, science platform engineers, and visualization tool builders to answer questions such as these. Time will be reserved at the end for participants to synthesize what they’ve learned into a report assessing the community’s needs and envisioning a roadmap for future work.

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Meet Our New Editor and Chat with AAS Publishing and Astrobites

The newest editor for the AAS Journals suite is Mubdi Rahman, the Founder and Principal of Sidrat Research. Mubdi’s research expertise spans a wide range of topics, with an emphasis on astronomical software. Want to meet him and talk about astronomy software and coding in the context of publishing? Mubdi will be around the AAS booth in the exhibit hall throughout the meeting during exhibitor hours!

In addition, if you want to chat with AAS Publishing, the following folks will be at the AAS booth throughout the meeting:

Julie Steffen, AAS Chief Publishing Officer

Janice Sexton, AAS Editorial Operations Manager

Frank Timmes, AAS Lead Editor of the High-Energy Phenomena and Fundamental Physics corridor

 

You can also request to meet with AAS Journals Editor in Chief Ethan Vishniac and the AAS’s Innovation Scientist and WorldWide Telescope Director Peter Williams.

You can find AAS Nova Editor Susanna Kohler, AAS Media Fellow Tarini Konchady, Astrobites Media Intern Luna Zagorac, and the rest of the Astrobites team at the Astrobites booth in the Graduate Fair throughout the meeting.

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Publishing Your AAS 238 Presentation in RNAAS

If your AAS 238 presentation is published as a research note, it receives a permanent, citable home within the literature and becomes available for all those unable to join us during the meeting. Research notes are short (up to 1,350 words, plus a 150 word abstract, with a single figure or table), moderated by AAS editors, and searchable on ADS. Research notes cover a remarkable diversity of topics, and do not preclude later inclusion of results in more substantial, refereed work.

We hope that the Focus on AAS 238 issue of RNAAS (as well as Focus on AAS 237 and Focus on AAS 236) will give the astronomy community a sense of the range of scientific work encountered at an AAS meeting, from colleagues who range from undergraduates presenting their research to those who have attended many meetings, virtual or otherwise.