Editor’s Note: This week we’re at the 242nd AAS meeting in Albuquerque, NM, and online. 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 for daily summaries, or follow @astrobites on Twitter for live coverage. The usual posting schedule for AAS Nova will resume on June 12th.

Table of Contents:

• Plenary Lecture: Meenakshi “Mini” Wadhwa (Arizona State University)

---

Plenary Lecture: Meenakshi “Mini” Wadhwa (Arizona State University) (by Lucas Brown)

The final plenary lecture of AAS 242 was given Thursday morning by Dr. Meenakshi “Mini” Wadhwa from Arizona State University on the role of sample return missions in exploring the past and present of our solar system. From Apollo to Mars Sample Return, these missions have and will continue to provide unique and invaluable insight into the formation of our solar system, the origins of life, and beyond.

Sample return missions, which are missions to collect material directly from extraterrestrial sources, have existed since the 1960s, beginning with the Apollo missions. While it has been possible to study extraterrestrial materials for much of human history through examining meteorites which land on the surface of Earth, the utility of meteorites is limited by the fact that we don’t have direct context for their origins; where a particular meteorite originated from in the solar system is often unknown. Additionally, when these objects come into contact with Earth’s atmosphere and surface, their properties and composition can change relative to when they were floating through space. On the other hand, space missions are limited in how much analysis they can do due to constraints on the size and mass of satellites that can be launched on existing rockets. Dr. Wadhwa explained that bringing samples back enables higher resolution and more precise analyses, and it also allows for experiments to be reproduced across numerous labs and with multiple techniques — all increasing the reliability of the results. Additionally, sample return missions greatly increase the number of researchers who can be involved in analysis, and these missions can inspire the broader public. To give a specific example of the impact of a past sample return mission, the return of lunar regolith and rock samples during the Apollo missions led to the finding of the first evidence of magma oceans in the Moon’s early formation history, which is now foundational in many theories attempting to explain the formation history of rocky planets.

While many robotic sample return missions have occurred in the decades since Apollo, Dr. Wadhwa focused much of her talk on Hayabusa2, a Japanese mission launched in 2014 to the asteroid Ryugu. This mission not only orbited and mapped the asteroid, but also landed on its surface several times, collecting samples of subsurface material by launching copper projectiles into the surface and collecting the ejected material in internal compartments. Through work done in part by Dr. Wadhwa and her collaborators, careful analysis of the composition of the asteroid was performed, including analysis of the titanium, chromium, and strontium isotopes present in the Ryugu samples. Understanding the presence of these elements can help us understand the distribution of materials in the protoplanetary disk from which our solar system formed, and it also allows us to determine the age of the asteroid, which closely matches the estimated age of the solar system (around 4.5 billion years).

Looking ahead to the future, Dr. Wadhwa spoke about Mars Sample Return (MSR), a proposed multi-step, multi-vehicle, multi-agency mission to return material from the surface of Mars. While such a mission has been proposed for many decades now, always claimed to be just “10 years away,” there now exists real funding and extensive planning to make this a reality within the next 10 years (for real this time). In fact, Perseverance — NASA’s newest rover, which landed on the surface of the red planet in 2021 — has already begun the process of collecting interesting sample material, dropping sample canisters along the way for future missions to retrieve. Such a retrieval will require the launch of additional spacecraft, one of which will land on the surface, intake the sample canisters, and then launch them into orbit with an on-board miniature rocket. The samples, once in orbit, will be retrieved by another craft and flown back to Earth. This plan is complex, introducing many never-before-demonstrated procedures, such as the ability to launch a payload into orbit from the surface of another planet. The intense efforts involved in MSR go to show the immense interest that exists within the scientific community for sample return missions.

Return to Table of Contents.

Editor’s Note: This week we’re at the 242nd AAS meeting in Albuquerque, NM, and online. 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 for daily summaries, or follow @astrobites on Twitter for live coverage. The usual posting schedule for AAS Nova will resume on June 12th.

Table of Contents:

• Plenary Lecture: John O’Meara (W.M. Keck Observatory)
• Press Conference: Get Ready for the North American Solar Eclipses
• Plenary Lecture: Joel H. Kastner (Rochester Institute of Technology)
• Plenary Lecture: Kathryne “Kate” Daniel (University of Arizona)
• Plenary Lecture: Klaus Pontoppidan (Space Telescope Science Institute)

---

Plenary Lecture: John O’Meara (W.M. Keck Observatory) (by Junellie Gonzalez Quiles)

The first plenary lecture of the day, titled “Now What? Making Astro2020 a Reality,” was given by John O‘Meara from W.M. Keck Observatory. He started by acknowledging the land that Albuquerque is on and acknowledging the Indigenous people of this land. He then talked about the Decadal Survey and how it has “controlled our destinies” since 1964. He showed the front pages of the decadal surveys throughout the years and mentioned the different missions that the various surveys prioritized. The Astro2020 Decadal Survey hopes to prioritize topics including Worlds and Suns in Context, New Messengers, and New Physics and Cosmic Ecosystems. John tried to put all of the priorities from the Decadal Survey in one question: How did the universe enable biology? With the recommendation of the Habitable Worlds Observatory (see Figure 1), he encouraged the attendees to think about it in two ways: Habitable Worlds (for looking for new worlds in the universe) and Observatory (for studying the mysteries of the universe).

John had a wish before the Astro2020 Decadal Survey was released: “I wish for a bold, visionary, pragmatic, and actionable report that not only sets the stage for scientific discovery that can change humanity, but also for a path for humanity to change how it does astronomy.” He shares that his wish was granted when the report came out! But, then he explained he felt like the fish in plastic bags floating in the ocean in Finding Nemo, asking himself, “Now what?” When thinking of this question, he realized that to enable great science, we need funding. He then evaluated the budget that we get to do astronomy research, which is around 0.025% of the US budget. John remarks that even though that seems like a tiny portion, it is still over one billion dollars! But, the current budget for the Astro2020 Decadal Survey is the Fiscal Year (FY) 2024 budget, which doesn’t have enough for the field to fulfill its goals. Therefore, we still need more funding for FY 2024, and John mentions that the budget is very similar to ping pong, where there is a lot of back and forth with the government to be able to get the necessary funding. He then says the budget is like a moving dumpster fire on a truck. But who is driving the truck? We are! John highlights the power we all have to make a difference in the budget and in general with policy matters. He emphatically says to “get out there and start talking!”

John nears the end of his talk by pointing out that we need a long term solution to how we operate facilities and that while the science leadership of the United States is at risk, there is still an immense opportunity to improve and strengthen it. “There is no such thing as a partisan photon,” he emphasizes, and impressed upon the audience that all political parties do care about science in their budgets, and we shouldn’t assume they don’t. John transitions to talking about JWST and how long it took to get the mission going and encourages us to think about how we can improve the process for the Habitable Worlds Observatory. He also highlights the different programs created for the Habitable Worlds Observatory and how we can all get more involved!

To conclude his plenary, he then highlights the importance of improving the state of the field, how crucial it is to support and lift the voices of the LGBTQ+ community as well as the voices of minority groups if we want to create a better environment for people to thrive in their search to understand the universe.

Twitter thread of plenary lecture by Junellie Gonzalez Quiles.

Return to Table of Contents.

---

Press Conference: Get Ready for the North American Solar Eclipses (by Sumeet Kulkarni)

The final press conference of AAS 242 focused on two exciting solar eclipses gracing North America within the next 12 months: the annular eclipse on October 14, 2023, and the Great North American total solar eclipse on April 8, 2024.

Angela Speck from the University of Texas at San Antonio, and part of the AAS solar eclipse task force, introduced these two events and emphasized how rare they are to occur so close to each other, especially taken in conjunction with the 2017 total solar eclipse. Eclipses themselves aren’t rare phenomena on a global scale, Speck said. Our planet is treated to one every year, but when considering one given location, they only arrive around once every 375 years! San Antonio, where Speck is based, is incredibly lucky to be witnessing both upcoming eclipses. She gave an overview of how these two events are different. The October 14 eclipse is an annular eclipse, wherein the Moon will be at its apogee or the farthest point in its elliptical orbit. Hence, it won’t quite cover the full disk of the Sun, leading to a “ring of fire” forming around the Moon’s outline. While a strip of land stretching from the northwest to the southeast portion of the continent will observe “full annularity” with the ring of fire, the entire continent will be able to see a partial solar eclipse, Speck said. Within six months, April 8, 2024, will see a more magnificent total eclipse where the Moon will completely block out the Sun, turning skies dark for about 4 minutes and enabling people to see the brilliant solar corona. The path of totality in this eclipse will also cut across North America diagonally, but this time from the southwest to the northeast.

Rick Fienberg, who leads the AAS solar eclipse task force, followed Speck by providing tips and guidelines on how to experience these eclipses, particularly the 2024 total solar eclipse. “You may want to drive the shortest distance (to totality),” he said, “but an important consideration is to look up the expected cloud cover at that time of the year.” Here is one resource that can help us keep track of this. Only going into the path of totality can offer one the complete eclipse experience. The Sun is so bright that our pupils do not start dilating to compensate for the decrease in light even when it is 75% blocked. Even when it’s 95% blocked (e.g., in an annular eclipse or 5 minutes before totality), it is still as bright as a cloudy day. “There is no such thing as a 99% total eclipse. It’s all or nothing,” Fienberg said.

Fienberg went on to stress the importance of safety in eclipse viewing. It is safe to look at the Sun with the naked eye (and even binoculars and telescopes) ONLY when it is completely blocked during totality — but one should be very careful to know exactly when totality ends. At any other time during the eclipse, or during a partial eclipse or even during the maximum coverage of an annular eclipse, everyone absolutely needs to wear protection. Safe solar filters only transmit 1 part in 100,000 of the sunlight intensity. Fienberg advised buying eclipse glasses and filters that pass standards or from suppliers listed on this AAS page. Detailed information on how to safely observe the eclipse is also available on https://eclipse.aas.org/.

Jayne Aubele from the New Mexico Museum of Natural History and Science next gave a local flavor of observing the October 2023 annular eclipse from Albuquerque, which she labeled as ground zero for this eclipse. It is expected to begin around 9:15 am and last almost three hours. The full annularity will start from 10:34 am and last 4 minutes and 45 seconds. To add further excitement, October 14th is also the last Saturday of the renowned International hot air balloon fiesta in Albuquerque! However, for anyone hoping to enjoy a dual balloon-eclipse ride, Aubele noted that the last balloon comes down well before the time full annularity will hit.

The following two presentations were given by Craig DeForest and Cherilynn Morrow, representing the Southwest Research Institute and NASA’s Polarimeter to UNify the Corona and Heliosphere (PUNCH) mission. DeForest spoke about Citizen CATE (Continental-America Telescopic Eclipse), a novel experiment that aims to capture images of the inner solar corona using a network of more than 60 telescopes operated by citizen scientists, high school groups, and universities. While the total solar eclipse will only last about four minutes from any given location, anyone interested in studying the Sun’s corona would not see it change much during this time. However, with the help of volunteer citizen scientists across the entire path of totality, the Citizen CATE project plans to make a 60+ minute movie of the Sun as it is blanketed by the Moon and showcasing its brilliant corona. These results will help augment PUNCH, NASA’s own mission that studies the solar corona.

Morrow followed up by stressing the importance of connecting our own eclipse viewing experience with that of other cultures and people belonging to generations preceding us. To this effect, NASA PUNCH aims not to have target audiences, but collaborators, including Native American/Hispanic youth and families, as well as blind and low-vision learners. “There are some cultures that don’t want to look at the eclipse” that we need to be cognizant of, Morrow said. Some people will be fasting and praying — it’s important to know this as we prepare our community outreach efforts. She concluded by reminding us about how ancient people witnessed the same phenomenon here that we are about to, by showcasing the fascinating eclipse petroglyph from the year 1097 AD in Chaco Canyon close to Albuquerque. These stone carvings possibly represent a total eclipse during high solar activity (lots of coronal spikes) and a nearby Venus!

Live tweets of this session by Sumeet Kulkarni.

Return to Table of Contents.

---

Plenary Lecture: Joel H. Kastner (Rochester Institute of Technology) (by Wei Vivyan Yan)

This plenary talk was delivered by Dr. Joel H. Kastner from the Rochester Institute of Technology. Dr. Kastner shared the latest studies on planetary nebulae (PNe; singular PN), which impact fundamental topics such as products of asymptotic giant branch (AGB) nucleosynthesis, late stages of interacting binary systems, origins of white dwarfs, and jet launching.

Dr. Kastner first introduced where PNe are located in the stellar evolution diagram (Figure 1). When a solar- to intermediate-mass star (~0.8–8 solar masses) grows old and moves away from the main sequence, it enters the AGB region, where its stellar envelope ejects and its stellar core rapidly is rapidly exposed. Intense ultraviolet emission ionizes the envelope when the core hits a temperature of ~30000K, which creates a glowing nebula. Eventually, this PN disperses and evolves into a white dwarf. The star loses ~30%–80% of its initial mass during this process. Therefore, as white dwarf generators, PNe document the “end game” of stellar evolution and provide unique insight into the initial-to-final mass relation from the stellar mass loss.

Dr. Kastner then showed the “classical” structure model of PN formation (left panel in Figure 2), demonstrating different layers and interacting winds inside a PN. When the AGB star ejects its envelope, the inner shock produces fast winds (velocity ~1,000 km/s) and forms the inner layer called the “hot bubble.” Dr. Kastner presented many X-ray observations as the key to unveiling wind interactions. For example, we can see very clear shells and layers in the images from ChanPlaNS (Chandra X-ray survey of PNe), which revealed the “hot bubble” and central stars emitting X-rays (right panel in Figure 2).

PNe have different morphologies, such as round/elliptical, hourglass/bipolar, and multipolar/point symmetric. Dr. Kastner took a deeper look at the bipolar morphology, which contains two lobes, a pinched waist, and a binary companion inside a torus structure (Figure 3). Dr. Kastner noted that the origin of the torus and the bipolar shape that may be caused by the binary companion is a longstanding problem. Whether the center should be a single star or a binary system is still debatable. According to a previous review paper (Jones & Boffin 2017, Nature Astronomy), the binary hypothesis fits better in most systems compared to a single-star scenario. But details about PNe’s structures, formation, and evolution may be even more complicated.

Are some PNe products of multiple stellar systems? Dr. Kastner showed Hubble’s and Chandra’s overlaid views of NGC 7027 (Figure 4). We can see clear details of structures like shells and rings along with different outflows to study the shocking and shaping of this young PN. Similarly, Dr. Kastner was very excited about the publicly released Southern Ring Nebula (NGC 3132) images from the JWST early release observations. After emphasizing ionized and molecular gas distribution, this PN system, which was previously known for its visual binary central star, actually has five central stars! The latest Submillimeter Array carbon monoxide mapping also confirmed the existence of a multiple stellar system.

Dr. Kastner suggested two different (binary/multiple stars) origin stories for PNe with different morphologies based on how much molecular gas they have. Bipolar and ring-like nebulae contain rich molecular chemistry, observed by the Atacama Large Millimeter/submillimeter Array (ALMA) and the Submillimeter Array, and tend to dominate detections of molecular gas. On the other hand, round or elliptical PNe with X-ray-emitting bubbles generally lack detectable molecular gas.

Dr. Kastner concluded this talk with many open questions and future directions in PN research. In addition to the challenges in the binary hypothesis for PN shaping, Dr. Kastner wanted to use upcoming data and instruments (e.g., eROSITA, ALMA) to better understand how shocks persist, the spatial distribution of molecular masses, and the evolution of light-element abundances over cosmic time. “We are standing at the astrophysical crossroads,” says Dr. Kastner.

Twitter thread for this session by Wei Vivyan Yan.

Return to Table of Contents.

---

Plenary Lecture: Kathryne “Kate” Daniel (University of Arizona) (by Emma Clarke)

“This one is gonna be special,” said Grant Tremblay as he began to introduce the next plenary speaker, Kathryne “Kate” Daniel. “No pressure on Kate,” he added. If there was pressure, Kate Daniel didn’t show it. She began with a thanks for the introduction, followed by opening remarks of her own — in an Indigenous language of her ancestors. Translating, she repeated “Hi, I’m very happy to be here,” shared her name, and explained that she is of Comanche, Chickasaw, and European heritage. She conveyed honor and respect to her ancestors and the people who came before her, as well as her colleagues, the AAS, NSF, NASA, and the Heising-Simons Foundation, and recognized the Sandia and Ancestral Puebloan peoples, whose homeland AAS 242 is being held on.

She then explained a game her grandfather used to play with her. He would invite her to look at a bird, for example, and think about what the bird was thinking. Next, he’d ask her to imagine sitting on the back of the bird, and to think about what it felt like, what it looked like, and what the surroundings looked like. Finally, he would ask her to think like the bird, to be like the bird, and know like the bird. She explained that this was an important lesson in perspective; that there is no central perspective, much less her own, and that she exists in and with and in relationship to the world. She encouraged the audience to play this game during her talk.

The next part of her talk focused on her science: studying how galaxies evolve themselves. She explained that galaxies evolve within an environment, through mergers and gas accretion, for example, but the questions that interest her are about the internal work galaxies do to evolve themselves. She explained that a galaxy can be looked at as a composition of stars, or alternatively, as a set of orbits. Galaxy morphology is built from the orbits: when the orbits are populated, we get shapes, such as the boxy-peanut shaped bulge of the Milky Way Galaxy.

Dr. Daniel then explained the work that she and her students and other collaborators have done to study the internal evolution of galaxies and galaxy structure. In particular she discussed dynamical resonances, such as the “corotation resonance,” a way in which orbits can be rearranged in the disk of a galaxy without any other kinematic signatures. She explained that as orbits evolve, the morphology evolves and emerges. Another important takeaway is that there is rich structure in galaxies such as the Milky Way, which is not in an equilibrium state, but has the influence of spiral arms. She concluded by noting that the works she presented, which all aim to understand the structure and internal evolution of galaxies, try to understand the same problem from multiple perspectives and that this has led to deeper knowledge and understanding.

In the second part of her talk, Dr. Daniel spoke specifically in terms of two-eyed seeing, an approach which applies both Western and Indigenous perspectives. She started by showing an image of Mauna Kea from two perspectives: one showing the observatories on the top and the other a representation of the cultural importance of Mauna Kea. She argued that the two images are not mutually exclusive; that it is not astronomy or cultural significance, but rather “and.” She explained that the only way to find “and” is through relationships. Along this vein she highlighted community-based models of astronomy. In particular, she described Cosmic Explorer, a future experiment which she is a director of. This gravitational wave experiment is named 24 times in the ASTRO2020 decadal survey, which identifies the priorities of the astronomy community. (Dr. Daniel encouraged everyone to have a look at the appendices of ASTRO2020 to see the reports from individual panels, and not just the executive summary, which is a compilation of the reports!) Cosmic Explorer increases gravitational wave sensitivity (over LIGO) tenfold and promises unprecedented and transformation science, but not only that — it takes power sharing with the community to heart. This is notable in its management structure, which has directors for areas including DEI and Land Partnerships. She noted that we have not only the responsibility but also the opportunity to do things differently and think about power sharing models. For example, scientists work with the public even before naming a location for observatories.

Dr. Daniel then highlighted some things that have been important to her with regards to bringing different perspectives to the astronomy community. She discussed the Society of Indigenous Physicists, which she co-founded, and shared a photo from their first meeting (over Zoom!) in 2020. She invited everyone to check out their social media and website and encouraged anyone who identifies as Indigenous to contact her. Next she highlighted mentorship networks, explaining they are much more effective than one-on-one mentoring relationships, namely because a single individual cannot and should not be expected to meet all mentorship needs.

Dr. Daniel concluded by tying both parts of the talk together, explaining that two-eyed seeing is about gaining dimensions: in perspective, in problem solving, an understanding the universe, and in the manner in which we exist. She explained that the collection of dynamics — whether in galaxies or among people — leads to emergent dynamics. “We have the ability to guide ourselves into emergent structures to broaden participation and evolve into something we may not otherwise imagine.” With that, she thanked the audience — in English and the languages of the Comanche and Chickasaw.

Return to Table of Contents.

---

Plenary Lecture: Klaus Pontoppidan (Space Telescope Science Institute) (by Junellie Gonzalez Quiles)

The last plenary talk of the day was given by Dr. Klaus Pontoppidan from the Space Telescope Science Institute. He talked to us about the “Origin of Rocky Planets and their Atmospheres: A Rhapsody in Infrared.” He started by talking about the Roskilde Cathedral in Denmark, an example of a church that would take a very long time to make and those who started working on it would maybe not see the end result. He draws the parallel with astronomy and future observatories; these missions take years to build and future generations will be the ones using these telescopes. Klaus has been involved with JWST and is part of the team that produced the first images of the mission!

Through his talk he walks us through how our understanding of planets has evolved over time. Exoplanets were theorized for a long time, but were only confirmed a few decades ago. Millimeter interferometry also has helped demonstrate the existence of protoplanetary disks. Klaus also highlights that Earth is actually depleted in volatiles and mentions that Jupiter is mildly enriched, except for oxygen. Similarly, Klaus reminded us about the results from the Oberg+ 2011 paper that pure freeze-out models predict carbon-to-oxygen ratios higher than the Sun’s for planets outside of the snowline. Pebble drift and water vapor advection concentrates planet-forming mass, which leads to the question: once exoplanet atmospheres are connected to the chemistry of protoplanetary disks, where exactly do planet-forming regions lie?

The speaker then shows detailed images of protoplanetary disks where dark gaps can be seen at large radii, which leads to the question of whether planets could be forming at such large radii in these systems. For several years, the Spitzer spectra of planet-forming disks looked smooth, but another group published the first detections of water and organics. Klaus then thought to himself, could the Spitzer data reflect that? He went back to the Spitzer legacy surveys and removed some methods used to analyze the data and found water! Then to connect it with JWST, Klaus found JWST-MIRI does not trace water all the way out to the snowline. To finish the talk, the speaker talked about characterizing the chemical diversity of planet-forming regions and shared that there is an upcoming paper talking about many water lines detected through the survey!

Twitter thread of plenary lecture by Junellie Gonzalez Quiles.

Return to Table of Contents.

Editor’s Note: This week we’re at the 242nd AAS meeting in Albuquerque, NM, and online. 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 for daily summaries, or follow @astrobites on Twitter for live coverage. The usual posting schedule for AAS Nova will resume on June 12th.

Table of Contents:

• Hale Prize Lecture: George H. Fisher (University of California, Berkeley)
• Press Conference: Resolving Stars and Hunting Nearby Galaxies
• Plenary Lecture: Julia Blue Bird (National Radio Astronomy Observatory)
• Press Conference: Hot Jupiters and Hungry Black Holes
• Harvey Prize Lecture: Bin Chen (New Jersey Institute of Technology)
• Plenary Lecture: Linda Shore (Astronomical Society of the Pacific)

---

Hale Prize Lecture: George H. Fisher (University of California, Berkeley) (by Emma Clarke)

The Solar Physics Division awarded this year’s Hale Prize, which recognizes “outstanding contributions over an extended period of time to the field of solar astronomy,” to George Fisher of the University of California, Berkeley. His talk, “Understanding the Dynamics of Magnetic Field and Plasma in the Interior and Atmosphere of the Sun,” reviewed the contributions to the field by himself and collaborators.

He began by discussing solar flares. First he described what happens when a solar flare occurs. This begins with the reconnection of magnetic field lines in the solar plasma. These newly reconnected field lines are filled with energetic electrons (which we can see due to their collisions with ions in the solar atmosphere and subsequent bremsstrahlung radiation). An enormous amount of energy is released in the reconnection event and transported into the solar chromosphere. An outstanding question many years ago was what happened to the solar atmosphere when heated by the energetic electrons. In 1989, Fisher described the downflows of chromospheric plasma driven by these energetic electrons and developed a generalized theory for the flare-driven chromospheric downflow’s amplitude and time variation. These predicted downflows are now routinely observed. Later, researchers wondered whether the solar flare models could be applied to stellar flares — flares on other stars. Working with Suzanne Hawley, originally a grad student and now a professor at the University of Washington, Fisher applied solar flare models to stellar flares more generally.

Dr. Fisher’s second topic was magnetic fields on the solar surface. These fields most likely come from the tachocline, a transition region at the base of the convection zone with large shear. From the tachocline, magnetic active regions emerge at the solar surface as magnetic flux tubes. In the flux-tube model, the magnetic field is concentrated in a thin tube. The dynamics of the tube can be described by the forces acting on a thin 1D tube embedded in a 3D model of the solar interior. Fisher said that the flux tubes do an excellent job of explaining the observed relationship between how sunspots are “tilted” and their solar latitude (known as Joy’s law). Sunspots have the property where the leading side (in the sense of the rotation of the Sun) is more compact relative to the more broken-apart side that follows. He has argued that the higher field strength of the leading side allows the tube to better resist being broken apart by turbulent convection.

Next Dr. Fisher discussed work on determining which magnetic quantity best correlates with observed X-ray output of active regions on the Sun. With collaborators he found that X-ray output is best correlated with the unsigned (think absolute value) magnetic flux. Despite advances in understanding the relationship between solar magnetic fields and X-ray emission, reproducing an observed X-ray image with simulations has been a challenging problem; observed and computed images still do not show compelling agreement. Fisher and collaborators speculate that the main cause of the disagreements is in how the coronal loops are heated.

The final part of the talk was about efforts to develop a data-driven physics-based model of the 3D magnetic field above the photosphere. Dr. Fisher explained that such a model would require (1) a model for the evolution of the 3D magnetic field — such as a magnetohydrodynamic model or magnetofrictional model — and (2) a method to derive the electric field and/or velocity field from the photospheric magnetic field data in order to implement Faraday’s law, which describes the evolution of the magnetic field in time. Dr. Fisher discussed the challenges of the second requirement. While velocity along the line of sight can be determined with Doppler shift methods, the other two “horizontal” components are more difficult to estimate. In 2008, Fisher and Welsch developed the FLCT code, based on the Local Correlation Tracking (LCT) technique, to find the horizontal components of the velocity from magnetogram data. Their code can construct the velocity field using two images taken at slightly different times. FLCT has been applied to find flows in many different settings, some of which Fisher never imagined it would be used for! Two applications that he found surprising were deriving streamline maps of the flows and deriving proper motion flows from nebula images taken years apart.

The other approach to the second requirement is to determine the electric field. One option is to compute the poloidal–toroidal decomposition electric field from all three components of the magnetic field. Fisher and collaborators do this using a technique called PDFI, which stands for “poloidal–toroidal decomposition (PTD) plus Doppler plus Fourier local correlation tracking (FLCT) plus ideal.” Fisher says that this technique does a “pretty decent job” of reproducing the electric field. The electric field has now been computed using PDFI for most emerged active regions observed by the Solar Dynamics Observatory.

Dr. Fisher concluded by sharing his excitement for solar physics research and the many unsolved problems in the field. He proposed that we are entering a “golden age” of solar physics, especially with regards to solar magnetism.

Return to Table of Contents.

---

Press Conference: Resolving Stars and Hunting Nearby Galaxies (by Junellie Gonzalez Quiles)

The first press conference of the day was moderated by Dr. Kerry Hensley, AAS Deputy Press Officer, and she introduced the three speakers for the session. First up, we had Olivia Gaunt, a PhD student from Tufts University speaking about “Rare Signals from Stars in Triangulum Galaxy.” Olivia used the Keck II telescope and specifically the Imaging Multi-Object Spectrograph (DEIMOS) to observe the Triangulum Galaxy. The Triangulum Galaxy (Messier 33), is 2.73 million light-years from Earth and has an estimated 40 billion stars. Out of these stars, Olivia is interested in Wolf-Rayet stars, which are a rare class of emission-line stars that exist in an intermediate stage between big and hot O-type stars and Type Ibc supernovae. These stars are also typically characterized by an expanding bubble of ionized gas. Olivia specifically looked at Broad Emission Line Luminous Sources, also referred to as BELLS, in the Triangulum Galaxy. In one object (BELLS 1), the team saw exciting changes to the star’s emission over a 4-year timescale, which has not been observed before! Lastly, some of these objects are even an even more rare type of Wolf-Rayet stars, which gives a new insight to this area of astrophysics.

Next up, we had Jim Jackson from the Green Bank Observatory who talked to us about star formation triggered by an expanding bubble in the Nessie Nebula. The birthplaces of baby stars (protostars) are dense, cold, filamentary molecular clouds. When high-mass (greater than 8 times the mass of our Sun) stars are formed, they put large amounts of energy into the surrounding gas, which ionizes it and forms expanding bubbles (H II regions). This phenomenon drives the main question of the study: does this energetic feedback trigger or hinder star formation? To answer this question, Jackson’s team looked at the Nessie Nebula, an extremely filamentary infrared dark cloud, which is cold, dense, and opaque. The Nessie Nebula also contains the Nessie bubble in which they see a feature that looks like a question mark. They see the expanding bubble, which interacts with the filament and at their intersection they see a luminous protostar. Its location strongly suggests that the collision between the expanding bubble and the Nessie filament triggered star formation. To determine this, they used the Stratospheric Observatory for Infrared Astronomy (SOFIA) and the Australia Telescope Compact Array (ATCA) to observe the Nessie Nebula. Through detection of ammonia, they were able to see that there are signs of shock, which means the expanding bubble is slamming into the filament at supersonic speeds and the collision triggered a star to form. [Press release]

To finish off the press conference, we had Stephen Walker from University of Alabama in Huntsville talking to us about X-ray observations of a group of galaxies falling into the Coma Cluster. X-rays provide us with a view of the hot (100 million K) intracluster medium filling clusters. They allow us to observe how galaxies move and merge into clusters. The team used XMM-Newton to observe the Coma Cluster. They observe the infalling group NGC4839 that has a 1.5 million light-year-long tail behind it, and their new observations are the most detailed of an infalling group! The Coma Cluster is preceded by a shock front traveling at around 3 million mph. Their edge detections show ripples like Kelvin Helmholtz instabilities. Through studying the shape of its tail, they are able to constrain the properties of the gas such as viscosity, which is important for understanding how galaxy clusters grow through mergers. [Press release]

Twitter thread for press conference by Junellie Gonzalez Quiles.

Return to Table of Contents.

---

Plenary Lecture: Julia Blue Bird (National Radio Astronomy Observatory) (by Wei Vivyan Yan)

This plenary talk today was delivered by Dr. Julia Blue Bird from the National Radio Astronomy Observatory, sharing the latest discoveries on galactic properties and evolution with CHILES. Thanks to all the amazing instruments to study both neutral hydrogen (HI) and molecular hydrogen, “It is really an amazing time to be a radio astronomer,” says Dr. Blue Bird.

Dr. Blue Bird first introduced CHILES as “a pathfinder for future radio astronomy surveys.” CHILES is short for COSMOS HI Large Extragalactic Survey, a blind survey on the HI emission using the Karl G. Jansky Very Large Array (VLA), covering the part of the COSMOS field with no strong ratio continuum sources (Figure 1). Since the HI emission line is faint and requires long integration times to observe, HI studies with previous large surveys are mostly limited to the nearby Universe (up to z = 0.06). Anything beyond z = 0.25 is considered high redshift. With a 1000-hour single pointing, CHILES could observe the HI line up to z = 0.5, which is a huge step forward.

The primary goal of CHILES is to tell the story of individual galaxies. Here, Dr. Blue Bird used CHILES observation to examine the connection between the comic web and galaxy gas. Since CHILES provided us with the opportunity to study both local and large-scale environments beyond z = 0.1 for the first time, Dr. Blue Bird was able to extend this discussion to higher redshift regimes.

By identifying the filamentary network of the cosmic web over CHILES’ field of view, we can locate the distance between a galaxy and the filaments (Figure 2). The closer a galaxy lies from the filament, the less HI gas this galaxy owns. Therefore, in the regions close to the filaments, we tend to find redder, passive, and more massive galaxies. In addition to this HI gas fraction, galaxy orientation is also related to the galaxy location to the surrounding filaments. CHILES showed that low-mass galaxies generate spins that align with filaments by accreting onto the filaments, while high-mass galaxies generate spins perpendicular to filaments by merging along filaments, which agreed with theoretical predictions.

Dr. Blue Bird also examined the connection between star formation histories and galaxy gas, which appears as scaling relations. These relations also serve as excellent “sanity checks” for the data! Among all scaling relations (HI & stellar mass, specific star formation rate & stellar mass…) checked with CHILES data, Dr. Blue Bird’s favorite one is a very tight correlation between HI mass and disk diameter values directly from CHILES data (Figure 3). This relation suggests that the HI surface density remains nearly constant as the disks grow.

At higher redshift, Dr. Blue Bird also found some fascinating individual sources at high redshift. For example, a very exciting starburst galaxy at z = 0.38 observed with CHILES shows a large amount of CO and a surprisingly high star formation ratio. More like galaxies at z > 2! Although most detections of individual distant galaxies are generally limited compared to nearby galaxies, stacked spectra of those distant samples can demonstrate the average properties at high redshift. Stacked gas fraction seems to rise along higher redshifts, indicating a possible evolutionary trend. More tests are needed for these hints of the galaxy evolution!

Dr. Blue Bird concluded this talk with the potential and capability of CHILES. CHILES is ongoing and has already filled in many missing measurements and data points (Figure 4). It will make more significant contributions to the scientific community. Dr. Blue Bird also offered acknowledgments not only to the land but also to the students of the land at the end of this presentation.

Live tweets of this session by Wei Vivyan Yan.

Return to Table of Contents.

---

Press Conference: Hot Jupiters and Hungry Black Holes (by Lucas Brown)

Today’s second press conference was massive — ranging from investigations of massive Jupiter-like exoplanets and explosive nova events to new observations of a famous black hole binary and studies exploring the behavior of supermassive black holes in cosmic voids.

In the first of four presentations, Songhu Wang from Indiana University spoke on the aforementioned “hot Jupiters.” First showing a plot of semi-major axis versus mass for each of the planets in our solar system, Wang noted the prevalence of gas giants in our outer solar system led researchers to believe for a long time that the temperature gradient of our solar system allowed larger amounts of icy, solid material to exist farther from the Sun, causing the larger planets to form there. However, in exoplanet systems, it is actually incredibly common for Jupiter-sized planets to exist extremely close to their host star — hence, “hot Jupiters.” This discrepancy suggests that some additional mechanism must be bringing these planets inwards over time. Two popular models exist for this mechanism: “disk migration” and “high-eccentricity migration.” The latter method typically doesn’t permit hot Jupiters to end up in orbits close to other planets, so it has been of much interest to researchers to determine how “lonely” hot Jupiters are. While previous research has suggested hot Jupiters are indeed lonely, Wang and his team recently employed a method called transit timing variation to search for planets in orbits close to hot Jupiters, and they found evidence that such companion planets might be much more common than previously thought! Further research is needed to confirm this finding and explore its implications for planetary migration models, but it’s nice to think those hot Jupiters out there aren’t so lonely after all.

Next up was something much hotter than a hot Jupiter — a nova! Montana Williams from New Mexico Tech presented on new observations of a particularly strange nova. A nova is an astrophysical event that occurs when hot plasma accreting onto a white dwarf in a binary star system becomes hot enough to temporarily sustain a fusion reaction. The nova in question, dubbed V1674H, was imaged by a collection of radio telescopes collectively known as the Very Long Baseline Array (VLBA). This event was remarkably fast for a nova, as it dimmed 2 magnitudes over the course of just around one day. This observation marked only the second time a system like this was observed using the VLBA, and as a result the researchers were able to learn about the structure and dynamics of the ejected stellar material.

Stepping up in mass once again, Mauri Valtonen from the University of Turku announced a possible first-ever direct detection of light coming from a secondary black hole in a black hole binary. The binary system, denoted OJ287, has been studied for a very long time. There are even images on photographic plates of the system that date back to the late 1800s! Part of what makes this system interesting is that the ~12-year orbit of the secondary black hole means that astronomers can predict when the secondary black hole will cross the accretion disk of the primary black hole. Whenever this happens, the system gets significantly brighter. However, up until now it has been impossible to distinguish between light coming off of the accretion disk or jets of the primary black hole and light coming off of the secondary system. Valtonen’s team performed an analysis of recent disk crossings and believes a particular set of variable flares they found corresponded to gas rushing into a stable area around the secondary black hole known as its Roche lobe. If this is indeed what the team spotted, it would mark the first direct detection of light from the secondary black hole in a black hole binary system.

Following the theme of hungry black holes accreting gasses, the final presentation of the day was a report on initial results from a research project lead by Anish Aradhey, a student at Harrisonburg High School, on the properties of supermassive black holes (SMBHs) at the center of galaxies in cosmic voids. Cosmic voids are huge underdense regions that occupy around 50% of the universe’s volume while containing less than 20% of the universe’s galaxies. The motivation for this work was to explore the hotly debated theory that galaxy interactions and mergers cause central SMBHs to accrete more material (or as Aradhey puts it — ”snacking”). Galaxies in cosmic voids are the loneliest of them all, so they provide an interesting point of comparison for this theory. Aradhey and his team used more than 8 years of NASA WISE data to look for the variability of mid-infrared light galaxies, which is a different method than is commonly employed in looking for “snacking” SMBHs. Typically, measurements are made of a galaxy’s mid-infrared light at one moment, and researchers look for bright red signatures associated with accretion onto SMBHs. This method can misclassify systems which are active but highly variable, so this new work attempts to avoid this issue by focusing on variability in this part of the spectrum. Aradhey and his team ultimately discovered that midsize and dwarf galaxies tend to have more “hungry” black holes in cosmic voids than in the general population, possibly because their isolation allows gas to more efficiently transfer to the center. On the other hand, central SMBHs appeared less active in the cosmic voids for larger galaxies.

Live tweets of this session by Lucas Brown.

Return to Table of Contents.

---

Harvey Prize Lecture: Bin Chen (New Jersey Institute of Technology) (by Sumeet Kulkarni)

Every year, the AAS Solar Physics Division awards the Karen Harvey Prize to an early-career scientist who shows outstanding productivity within ten years of their dissertation. This year’s winner is Dr. Bin Chen, an associate professor of physics at the New Jersey Institute of Technology. Chen gave a plenary talk on using the Sun as a laboratory to study some of the most energetic plasma physics phenomena.

Chen said our closest star is a stepping stone to studying all stars in astronomy. Indeed, we use units such as solar mass and luminosity to base our understanding of various happenings in the universe. While we can’t go there in a lab coat, the Sun also serves as a great laboratory for all of stellar physics. First and foremost, it is BRIGHT, making it easy to track dynamic phenomena happening on its surface in human timescales. For example, a one-second exposure time is enough to image a rising solar flare that can change its shape and form within seconds. In contrast, other dynamic phenomena such as supernova outflows need hours of observing time to collect data and show changes over a timescale of years.

Additionally, we can study the Sun at multiple wavelengths and resolve it extremely well spatially as well as temporally. Chen and his solar physics colleagues have leveraged these abilities to understand solar flares in exquisite detail.

Solar flares release humongous amounts of energy, totalling up to 10³² erg — 10 million times greater than a volcanic explosion. The size of the corona participating in this release is equivalent to a large fraction of the size of the Sun, with the flare rising as high as 0.1 times its radius. The cause of this energy release is magnetic reconnection, a process wherein magnetic field lines of opposite poles approach each other, increasing the electric field and current density in a very thin layer called the “current layer.” This process also accelerates particles such as electrons up to very high speeds, close to the speed of light. Combining theoretical models and observations using the Very Large Array (VLA) and the Expanded Owens Valley Solar Array (EOVSA), Chen has added new insights to where and how this particle acceleration occurs in solar flares.

According to current theoretical models, a standard solar flare forms a long and thin current sheet that tapers in the middle, leading to high velocities of particles in this region. EOVSA can take frequent, broad-band microwave spectra of solar flares, from which it is also possible to distinguish spectra coming from within each region of a flare. This helps us study how magnetic fields vary within the flare structure.

Based on these data, Chen said the magnetic field profile of the observed current sheet matched very well with theoretical models. The field had a local maximum (around 500 Gauss) and minimum (called the “bottle”). The bottle portion had a lower magnetic field at the center surrounded by high fields at two ends. But unexpectedly, the spot with the maximum high magnetic fields has lower concentrations of energetic electrons, which are more prevalent in the bottle region.

Magnetic reconnections are seen in other places too: the Tokamak nuclear fusion prototype reactor and neutron stars. But they are especially important with planetary magnetic fields such as the Earth’s magnetosphere, which protects our atmosphere from evaporation due to solar winds and is thus crucial to sustaining life on our planet.

That is why it is important to study this physical process in further detail. Chen said the future observatories such as the Frequency Agile Solar Radiotelescope (FASR) would have the ability to resolve the shapes of solar flares like never seen before, as seen in the simulated image below. It is sure to flare up as many new questions as it answers!

Return to Table of Contents.

---

Plenary Lecture: Linda Shore (Astronomical Society of the Pacific) (by Ben Cassese)

The final plenary of the day offered something new for those who remained in the largest exhibition hall into the early evening: a talk not on astronomy research, but on public outreach and science communication. Dr. Linda Shore, the CEO of the Astronomical Society of the Pacific and winner of the 2023 AAS Education prize, split her time between a discussion of principles on how to effectively communicate with the public and anecdotes/examples from throughout her career as an educator.

After noting that science communication is more important than ever in the age of misinformation and proliferating conspiracy theories, Dr. Shore shared three keys to effective science education: all activities, whether hands-on museum demonstrations or sit-down lectures, should aim to foster participants’ Science Identity, Science Agency, and  Science Capital.

An effective way to hit all three areas is to let participants explore somewhat on their own and reach a conclusion through their own questioning. The Exploratorium, a museum in San Francisco where Dr. Shore worked for many years before joining the ASP, takes this concept to the extreme. From the moment they arrive, guests of all ages are presented with interactive exhibits that come with very few instructions. For example, a giant concave mirror that sat along one wall was not accompanied by any text explaining the concepts of basic optics, like a focal point or magnification. Even so, by approaching the mirror from different directions at different distances, visitors learned that the image flipped and warped depending on their viewing geometry. Many also discovered that sound behaves like light and can be focused as well, allowing them to whisper to a friend across the hall if they stood just the right distance from the mirror.

Although the Exploratorium educates the public about science, it also is a hub for teachers to teach teachers. Dr. Shore shared several classroom experiments developed during the long-running Exploratorium Teachers Institute, a forum for teachers to develop their own strategies for effective communication, often under the guidance of veteran teachers who went through the programs themselves.

Short on time, Dr. Shore unfortunately had to skip some of the recent initiatives she has spearheaded for practicing astronomers to better their own science communication abilities. But, they are many, and include the AAS-ASP Ambassadors Program and On-The-Spot Feedback Program.

We thank Dr. Shore for her informative and enjoyable presentation, and congratulate her on the well-deserved 2023 AAS Education Award!

Live tweets of this session by Ben Cassese.

Return to Table of Contents.

Editor’s Note: This week we’re at the 242nd AAS meeting in Albuquerque, NM, and online. 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 for daily summaries, or follow @astrobites on Twitter for live coverage. The usual posting schedule for AAS Nova will resume on June 12th.

Table of Contents:

• Fred Kavli Plenary Lecture: Dan Scolnic (Duke University)
• Press Conference: Discoveries in Distant Galaxies
• Oral Session: Daytime & Dark Sky Heritage in American Southwestern Archaeoastronomy
• Plenary Lecture: Edwin “Ted” Bergin (University of Michigan, Ann Arbor)
• Press Conference: Solar Swirls, Satellites, and Saving the Night Sky
• Plenary Lecture: Greg Taylor (University of New Mexico)
• Plenary Lecture: Jeyhan Kartaltepe (Rochester Institute of Technology)

---

Fred Kavli Plenary Lecture: Dan Scolnic (Duke University) (by Lucas Brown)

AAS started off tense this year — that is, it started with a presentation about two measurements that are in tension with each other. Professor Dan Scolnic of Duke University took the stage to give this meeting’s Fred Kavli Plenary Lecture, which focused on his work measuring the expansion of the universe with Type Ia supernovae. Over the past ten years, these sorts of “direct” measurements of the expansion rate (denoted “H₀”) have honed in on a value around 73 km/s/Mpc while precise measurements of the cosmic microwave background (CMB) combined with the standard model of cosmology have suggested a value around 67.5 km/s/Mpc. What gives?

The first portion of Prof. Scolnic’s talk helped bring us up to speed on the history of the Hubble constant and the idea of the expanding universe itself. More than 100 years ago, Einstein completed his general theory of relativity, and he set out to apply his new theory to the universe as a whole to understand its cosmological implications. Quickly, he found that in order to have a static, eternal universe, a constant term had to be added to his field equations — the “cosmological constant.” Einstein insisted for much of his life that any non-static models of the universe derived from his theory had to be wrong in some way, Prof. Scolnic noted, but the idea of a dynamic universe was eventually vindicated through observations. Those observations, carried out initially by Harvard astronomer Henrietta Leavitt and then expanded upon by Edwin Hubble, involved measuring the distances to far away galaxies using Cepheid variable stars, whose intrinsic brightness can be deduced from their period of brightening and dimming. By tracking the relation between the distance to a galaxy and the velocity at which it recedes from us, Hubble and his successors demonstrated the expansion of the universe.

Type Ia supernovae, like Cepheid variables, have an intrinsic brightness that can be tightly constrained. This, combined with their extreme luminosities, makes them ideal for measuring the expansion of the universe on even larger distance scales. Precise measurements of this expansion using supernovae revealed that the universe is not only expanding but accelerating, which encouraged the re-introduction of Einstein’s cosmological constant into cosmology. Today, measuring the expansion rate of the universe H0, as well as the value of the acceleration, are major aspects of observational cosmology. Prof. Scolnic works in large collaborations like Pantheon+ and SH0ES to measure these values using Type Ia supernovae and other objects with well-constrained intrinsic brightness, known as “standard candles.” The process of combining distance measurements from different types of standard candles to estimate farther and farther distance scales is known as the “distance ladder” method. In contrast, one can also infer H0 from measurements of the CMB. Prof. Scolnic likened this approach to looking at a human growth chart: the CMB acts as a “baby picture” of our universe, and when we combine this picture with a cosmological model we can generate an expected growth-chart to predict the properties of the universe today. However, in recent years it has become clear that CMB measurements are predicting a lower value of H0 today than is actually measured using the distance ladder technique.

This discrepancy, known as the “Hubble tension,” has led to large amount of criticism being levied at the work of Prof. Scolnic and his collaborators, as some believe the tension is most easily explained as being the result of systematic errors in their analysis. However, Prof. Scolnic and his teams have worked diligently over the past several years to address these concerns. In his presentation, Prof. Scolnic demonstrated how even tweaking over a dozen aspects of their analysis couldn’t get H0 below about 72.5 km/s/Mpc, still far from the 67.5 km/s/Mpc derived from CMB measurements. Removing entire “rungs” on the cosmic distance ladder also fails to resolve the tension. Prof. Scolnic believes that their measurements are indeed correct, and that part of why other physicists are so apprehensive about the analysis is that there isn’t anything immediately obvious on the theoretical side that can fix the tension. In many theoretical explanations, a radical change in the dynamics of the universe must occur at either very early or very recent times. Prof. Scolnic largely dismisses the latter conclusion, highlighting a paper that speculates on the possibility that a rapid change in the gravitational force ~100 million years ago may have occurred, coinciding with the extinction of the dinosaurs. The bizarre connection here is meant to demonstrate how sparse the evidence is for these recent-universe changes. On the other hand, Prof. Scolnic thinks some theories which modify early-universe dynamics may be promising, such as “early dark energy.” Regardless of what exactly turns out to resolve the Hubble tension, there is clearly a lot left to learn about the history of our universe.

Return to Table of Contents.

---

Press Conference: Discoveries in Distant Galaxies (by Sumeet Kulkarni)

The press office at AAS 242 decided to begin their press conference schedule from a long, long time ago and in galaxies far away, with subsequent press conferences bringing us gradually closer to home by Wednesday. This first one, though, was all about discoveries in distant galaxies using new-age probes that extend humanity’s sense-making capabilities almost beyond comprehension — through gravitational wave detectors such as LIGO and Virgo and telescopes like JWST.

First up, representing the “audible” sector of astronomy — listening to the “sounds” of spacetime via gravitational waves — was Ore Gottlieb from Northwestern University’s Center for Interdisciplinary Exploration and Research in Astrophysics. While detectors such as LIGO and Virgo now regularly catch the chirps from merging binary neutron stars and black holes, there are other, yet undiscovered sources of gravitational waves that researchers hope to uncover in their fourth observing run (O4). One of these is catching the combined cacophony of gravitational wave sources, also known as the “stochastic gravitational wave background,” as opposed to hearing individual events. While compact binaries also contribute to this background, Gottlieb focussed on two additional possibilities that can set spacetime in motion: Supernovae and the progenitors of gamma ray bursts (GRBs). The latter can create extended “cocoon” structures powered by jets in 20-40-solar-mass stars, and these promise to be the most likely stochastic background candidate. However, Gottlieb noted that there is only about 1% chance of detecting cocoon signatures in O4, and realistically, we will need third-generation observatories. [Press release]

Next up was a trio of presenters unveiling new results from the JWST-JADES project. JADES, short for the JWST Advanced Deep Extragalactic Survey, is a massive hunt for galaxies especially from the early universe (when it was only around 600 million years old). In late 2022, the team broke the record for the earliest discovered galaxy, and they expect to keep breaking milestones as new data rolls in.

The first speaker, Marcia Rieke from Arizona State University introduced the JADES project and its latest data release. This was followed by Kevin Hainline from the Steward Observatory who gave an outline of exactly how early of an universe their team is probing. JADES’ dataset of galaxies from less than 600 million years since the Big Bang now numbers at 717, up from only a dozen or so before JWST! “It’s exciting that we can even talk about these (early) times,” Hainline said. More than 93% of these galaxies, which formed the early hydrogen and helium crucial for the evolution of our universe, were never seen before JWST. But now, not only can we detect these infant galaxies, but we can also see complex structures in them, including one dumbbell-shaped early galaxy which is Hainline’s favorite. [Press release]

Ryan Endsley from UT Austin gave the next JWST update about dwarf galaxies. He said that ultraviolet emission lines from the recombination of hydrogen ions are valuable probes of star formation in early galaxies. In particular, they are great probes to study dwarf galaxies, given JWST’s ability to detect emission lines from galaxies that are 50 times fainter than what was possible before. It is now also possible to compare whether bright and faint galaxies from the early universe developed differently. And indeed, the JADES team found that the brightest galaxies underwent more star-formation bursts — events wherein matter equivalent to several tens of Suns formed at once. [Press release]

The next presentation emitted smoke, not quite from fireworks, but from a new discovery that definitely warrants setting some off — that of complex organic molecules in early galaxies. Jane Rigby presented these results from the TEMPLATES project, which uses JWST observations of four distinct galaxies. She made sure to spotlight two researchers to be credited with this discovery: Justin Spilker from Texas A&M University and Kedar Phadke from the University of Illinois. Through observing a galaxy 12 billion light-years away that got bent, warped and magnified by a closer clump of galaxies 3 billion light-years away in what is known as gravitational lensing, the team could make out signatures of organic molecules that lead to smoke or smog-like structures in their images. [Press release]

The final press briefing of this morning was given by Patrick Kamieneski from Arizona State University, who talked about a dusty and warped Milky Way-like galaxy nicknamed “El Anzuelo.” Spanish for a fish-hook, this term aptly describes the shape of this galaxy which is 11 billion light-years away. While similar in size and a dustier version of our own galaxy, El Anzuelo forms stars at more than 80 times faster than the Milky Way. JWST’s incredible infrared detection capabilities have made it possible to dramatically improve the way in which we can study such objects, as emphasized by the image below.

Return to Table of Contents.

---

Oral Session: Daytime & Dark Sky Heritage in American Southwestern Archaeoastronomy (by Emma Clarke)

Tony Hull from the University of New Mexico started this session by discussing a simple and accurate method to define cardinal directions. In an experiment in Chaco Canyon, New Mexico, researchers used a portable light stand constituting a gnomon and pebbles to track the trajectory of the gnomon shadow. They showed that on the equinox, the tip of the shadow follows a straight line, oriented accurately east–west. They concluded that the equinox gnomon is sufficient to establish the cardinality of the Great House Pueblo Bonito in Chaco Canyon. However, this is not ethnographic evidence that the method was used, rather that it could have been used.

Next up, Cherilynn Morrow discussed the outreach program associated with NASA’s PUNCH mission: four “suitcase-sized” spacecraft focused on the inner heliosphere between the Sun and Earth that is scheduled to launch in 2025. The PUNCH outreach program focuses on the sun as a natural extension of the human understanding of the sun and its rhythms. The program shares the interconnections between historical sun watching, such as interpreting the “eclipse” petroglyph site at Chaco Canyon, and modern Sun-watching, both by NASA missions and all contemporary people observing sunrise, sunset, light and shadow cast by the Sun, and eclipses.

The third speaker, J. McKim Malville, discussed the astronomy connected with the Great Houses in Chaco Canyon and what it meant for the inhabitants, residents, and visitors during astronomical events. One unanswered question is why the 15 Great Houses were built in such a resource-poor location and not totally abandoned when leaders moved northward. Perhaps the canyon and buildings were sacred places with astronomical significance.

Closing the session, Michael Rymer spoke briefly about archaeoastronomy and international dark sky places. The International Dark-Sky Association’s International Dark Sky Places Program encourages areas around the world to preserve dark sites through policies and public education. Two dark sky places in the US — Chaco Culture and National Historic Park in New Mexico, and Hovenweep, on the border of Utah and Colorado — are also archaeoastronomical sites. Protection of the dark night sky at these places not only makes better stargazing, but is also important for preservation of wildlife and plants. There is a growing list of potential future sites of dark-sky parks in the US.

Return to Table of Contents.

---

Plenary Lecture: Edwin “Ted” Bergin (University of Michigan, Ann Arbor) (by Junellie Gonzalez Quiles)

Murthy Gudipati from the Jet Propulsion Laboratory (JPL) introduced the Laboratory Astrophysics Division and invited everyone to become familiar with the division and join as members. He then introduced the plenary speaker, Prof. Edwin “Ted” Burgin from the University of Michigan, Ann Arbor. His talk titled “The Birth of Planets and the Story of Carbon” started with his recognition of laboratory astrophysicists and their role in helping understand the fundamentals needed to study astrophysical phenomena. Ted then transitioned to mentioning how the search for life has driven the connection between chemistry in protoplanetary disks to the atmospheric composition of exoplanets. This link is essential if we want to fully understand how planetary systems are formed and, therefore, how individual exoplanets are formed.

Throughout his talk, he took us on a journey where he explained what protoplanetary disks look like, how there are dark gaps or rings, which can mean that planets may be forming in that region, and explained to us one of the ways you can create exoplanets: pebble accretion. Through planet formation, exoplanets can have different bulk compositions depending on where they form and whether they are mainly made of refractory, semi-volatile, or volatile elements. Öberg et al. 2011 shows the relationship between the carbon to oxygen ratio (℅ ratio) and the snowlines in a planetary system, and Ted mentioned that in systems that have a ℅ ratio higher than 1, we know that oxygen must be present as ice on grains. Knowing the carbon to oxygen ratio is important to understand in the context of planet formation.

During his plenary, he also spoke about isotopic fractionation and how it offers a new window into planet formation. He showed the TW Hya system, where they looked at the ratio of ¹²C to ¹³C. This can be done for other planetary systems to say whether the system could be carbon rich (see Figure 1). He then ended his talk by talking about our own planet. Earth is relatively carbon poor compared to our Sun, Venus, and other types of chondrites (see Figure 2). Earth was formed of mainly refractory materials with small amounts of soot and water, and he aims to understand soot in the context of exoplanets. He also studied the geological processes that could lead to outgassing on exoplanets and how the carbon inventory can lead to methane in their atmospheres and potentially hazes as well.

He is very interested in how all of these aspects of planetary formation and evolution could impact the habitability of exoplanets, and it is certainly something to look out for in our search for life in other worlds!

Return to Table of Contents.

---

Press Conference: Solar Swirls, Satellites, and Saving the Night Sky (by Lucas Brown)

The second press conference of the day switched gears from the distant reaches of the universe to our local corner of space, with presentations on a new solar weather phenomenon, the positives and negatives of artificial satellites for astronomy, and updates on efforts to preserve the night sky.

First up was Oana Vesa from New Mexico State University, who spoke on new research into solar tornadoes. That’s right — there are tornadoes on the Sun. Only discovered in 2008, there is little known about the formation mechanisms behind these tornadoes or their overall role in the solar environment. Vesa explained that these tornadoes, consisting of hot, swirling plasma, are bound to the surface of the Sun magnetically, and can channel mass and energy up through different levels of the solar atmosphere. And like most things on the sun, their scale is massive. These chaotic solar vortexes vary from the size of a city all the way up to the size of Earth. Through new observations performed at the Dunn Solar Telescope, Vesa’s team has tracked dozens of these events, and they have begun the process of cataloging and analyzing their behaviors. So far, the team has found the tornadoes to have an average lifespan of about 8 minutes, and some have been seen to form in pairs or exhibit chaotic spiraling patterns. There’s a lot left to learn about these fiery storms. [Press release]

Next up was Justin Albert from the University of Victoria, who gave an overview of ORCASat, a recent cubesat mission that intends to demonstrate the utility of specialized satellites for calibrating ground-based telescopes. ORCASat contains a specialized cavity known as a Lambertian sphere, which evenly disperses incoming laser light before some of that light reflects down towards Earth. This system allows for on-board photodiodes to very accurately measure the intensity of light which will be beamed through the atmosphere. In turn, ground-based equipment can observe the satellite in orbit and determine how much light was lost as it passed through the atmosphere, providing a very sensitive method of calibration. The satellite has been in orbit since November of last year, and in the ensuing months, one complete exposure (in good lighting conditions) has been taken of the satellite streaking across the sky, providing a first proof-of-concept of the method. NASA and NIST are expected to develop a more advanced satellite for this purpose in the future, which will hopefully help increase the accuracy of measurements taken by ground-based telescopes. [Press release]

While satellites like ORCASat may help increase the accuracy of ground-based astronomy through its intentional emission of light, most satellites in orbit are actually detrimental to ground-based astronomy due to their reflection of light, occasionally creating bright streaks in astronomical imagery. For this reason, astronomers around the world have been working on developing algorithms to automatically detect such streaks and remove them or toss out the affected imagery. David Stark from the Space Telescope Science Institute (STScI) spoke on this in his talk, highlighting the development of a new algorithm which greatly increases the accuracy of satellite-trail detection. The algorithm employs a method known as a “Median Radon Transform,” which essentially looks for the median pixel brightness in every possible straight line one could trace within an image. A large outlier in a given line’s median value is a strong sign that that line contained an abnormal amount of light, often due to a satellite trail. This method significantly improved satellite-trail detection over previous methods developed at STScI. In testing the method on Hubble Space Telescope (HST) data, Stark and his team found that the number of satellite trails in HST imagery had roughly doubled over its lifetime, but noted that the rate was still so small that it did not hinder HST’s ability to do science. [Press release]

Closing out today’s second press conference, James Lowenthal from Smith College spoke about efforts to protect the night sky from light pollution. He noted that terrestrial light pollution from cities is in many ways a more significant threat to astronomy than satellite trails, and has many other negative effects such as harming plants and animals which are all used to a particular day-night cycle that has been disrupted in recent years. He also highlighted the spiritual significance of the night sky to many native communities. Lowenthal noted that dark sky advocacy groups have grown in recent years thanks in part to renewed interest due to the growth of satellite mega-constellations like SpaceX’s Starlink. Through the efforts of dark sky groups and their partnerships with native communities, local governments, and industry, some strides have been made towards preserving the night sky, such as creating new lighting standards centered around preserving the night sky while still illuminating cities. However, much more work has to be done given that recent research has shown that light pollution is increasing at much higher rates than previously thought due in part to the proliferation of LEDs. One of the success stories Lowenthal highlighted in his talk was the protections enacted in Coconino County, Arizona, home to numerous historic observatories. Another recent example given was the enacting of official dark sky protections in central Maine, one of the last remaining dark sky sites east of the Mississippi River. [Press release]

Return to Table of Contents.

---

Plenary Lecture: Greg Taylor (University of New Mexico) (by Ben Cassese)

Greg Taylor of the University of New Mexico delivered the third plenary of the day. Over the course of 45 minutes, Prof. Taylor took the denizens of Ballroom C and the Zoomiverse on a whirlwind tour of science conducted with the Long Wavelength Array (LWA) over the past decade. This instrument, a collection of 256 individual antennae spread throughout a 100-meter ellipse, has touched an impressive number of subfields in that time: From pulsars to the solar wind, the LWA has seen (and measured) it all.

After joking that his talk would last 6 hours and cover each of the roughly 80 papers built on LWA data, Taylor settled for summaries of some of the highlights. Many of these centered on the detection and characterization of meteors as they streak through the atmosphere and leave a wake of radio-bright ionized material trailing behind. There was a satisfying arc to this line of research: When Taylor and collaborators first saw these brief signals, they did not know what to make of them. They could think of no astronomical source for these transients scattered evenly throughout the sky, and only with careful analysis and cross-checking with other techniques did they realize that they had built a uniquely capable meteor detector. The team has since made the study of disintegrating meteors and their fireballs a major research focus.

Taylor also shared an overview of observations designed to test models of the solar wind. Here, the LWA stared at a pulsar (during the day! Radio astronomy is great like that) and measured how its signal changed as the Sun edged closer and closer to their line of sight. This let the team probe different regions of interplanetary space and constrain the ionized material that hovers within the solar system and slightly distorts radio signals.

After including very brief overviews of a few other projects, Taylor pivoted to the future of the LWA. The team has already constructed a second, similar array far from the original, which they can connect to form a longer baseline and better angular resolution. In the coming years, they hope to repeat this improvement in the extreme and build a “swarm” of small arrays dispersed across the United States. Some of these sites are purely aspirational, but some already have committed funding; in all, it looks like the next decade will be even more productive than the last.

Return to Table of Contents.

---

Plenary Lecture: Jeyhan Kartaltepe (Rochester Institute of Technology) (by Sumeet Kulkarni)

“Far and wide eyes of the JWST” was the theme of the final plenary session at AAS 242 on Monday. Prof. Jeyhan Kartaltepe from the Rochester Institute of Technology talked about results from two wide-ranging projects from the first JWST observing cycle and how they are constantly molding our knowledge of cosmic history.

Kartaltepe began with a brief overview of JWST’s capabilities and how its infrared eyes unlock the deepest reaches of the universe by detecting light that has been redshifted to those wavelengths due to cosmic expansion. JWST was always going to be pathbreaking, and all astronomers knew it. When asked how many in the plenary woke up early (in US time zones) to watch it launch on Christmas day in 2021, 90% of the hall raised its hands.

The first project Kartaltepe’s plenary featured was CEERS, which observes a 100 square arcminute patch of the sky to demonstrate, test, and validate efficient extragalactic surveys. An early science result from CEERS was the discovery of a faraway galaxy, now known as Maisie’s galaxy after the daughter of one of the project PIs. Maisie’s galaxy looks like a red blob among a sea of usual-looking galaxies, as is typical for such early galaxies. But the interesting thing was that it wasn’t a standalone galaxy in CEERS data! There were several more candidates found in JWST images, challenging our understanding of how quickly galaxies started to form and mature in our universe.

But among the exciting early galaxy candidates also hide several mimickers: nearby, dusty galaxies also have the same red, blobby appearance which can be mistaken to be one due to high redshift by photometry (studying properties of the images) alone. But JWST does much more than just click pictures of these galaxies. It can also study their character using a spectroscope, or a prism that splits light to unveil the telltale signatures of molecules within it. The spectroscopic data from JWST of Maisie’s galaxy was so clean, that it “looked just like that of a nearby galaxy,” said Kartaltepe. This helped them confirm its age of being only around 390 million years after the Big Bang! Spectroscopy also helps confirm (or reevaluate) the age of early galaxy candidates. Kartaltepe gave an example of a galaxy first believed to have a redshift of 16 (placing it among the earliest ever detected galaxies), which was then reduced to 4.9 thanks to the JWST’s NIRSpec data.

The second project that Kartaltepe is excited about is Cosmos-Web. This project covers a relatively big patch of the sky, just larger than the full Moon, but goes deep into it with JWST’s far-reaching eye to record all galaxies near and far that lie within. This patch of the sky was chosen because part of it has been extensively studied by the Hubble space telescope, allowing for extracting science out of the two sets of observations in tandem. As of today, Cosmos-Web has completed about half of its observations and is already finding large numbers of high-redshift galaxy candidates, dusty star-forming galaxies, and more!

Kartaltepe concluded her plenary by stressing the importance of mentorship in furthering our field and supporting the progress of students and early career researchers. “I wouldn’t be here if not for excellent mentors,” she said, and urged all students today to pick an advisor who prioritizes seeing them as a person first.

Return to Table of Contents.

This week, AAS Nova and Astrobites are attending the American Astronomical Society (AAS) summer meeting in Albuquerque, NM, and online.

AAS Nova Editors Kerry Hensley and Susanna Kohler and AAS Media Fellow Ben Cassese will join Astrobites Media Intern Sumeet Kulkarni and Astrobiters Lucas Brown, Emma Clarke, Wei Vivyan Yan, and Junellie Gonzalez Quiles 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! You can also follow @astrobites on Twitter for the latest updates.

Where can you find us during the meeting? We’ll be at the Astrobites booth in the Exhibit Hall all week — stop by and say hello! In addition, you can catch Kerry, Ben, and Sumeet at the press conferences all week, and Sumeet will be presenting an iPoster on Astrobites as an educational resource at 5:30–6:30 pm MT on Tuesday, 6 June.

You can read the currently published AAS 242 keynote speaker interviews here. Be sure to check back all week as the remainder are released!