AAS 229

Greetings from the 229th American Astronomical Society meeting in Grapevine, Texas! This week, along with several fellow authors from Astrobites, I will be writing updates on selected events at the meeting and posting at the end of each day. You can follow along here or at astrobites.com, or catch our live-tweeted updates from the @astrobites Twitter account. The usual posting schedule for AAS Nova will resume next week.

If you’re an educator who will be at the meeting and you’d like to learn how to use digests like AAS Nova or Astrobites to bring current astronomical research into your classroom, you can still register on-site for Astrobites’ workshop on the subject, “Introducing Current Research Into Your Classroom“, which will run Wednesday, 12:30–2:00 pm in Appaloosa 1.

Otherwise, we hope to see you around at Grapevine! Drop by and visit AAS, AAS Journals, and Astrobites at our joint booth in the Exhibit Hall (Booth #317) to learn more about AAS’s new publishing endeavors, pick up some Astrobites swag, or grab a badge pin to represent your AAS journals corridor!



AAS Publishing News

Are you an astronomer considering submitting a paper to an AAS journal (i.e., AJ, ApJ, ApJ Letters, or ApJ Supplements)? If so, this post is for you!

Earlier this year, the AAS released a new version of the LaTeX class file AASTex, used to prepare manuscripts for submission to AAS journals. You can read about the new features that were included in AASTex 6.0 here.

style comparison

Comparison of three of the six available layout styles. Shown are “modern” (top), “default” (middle), and “twocolumn” (bottom).

The publishing team received very helpful feedback from authors in response to that release, and your requests have now been incorporated into an updated version: AASTex 6.1. This file contains all the same new features of AASTex 6.0, plus a few additional tweaks to make preparing your manuscript even easier! Read on to find out what’s new in AASTex 6.1, available for download now.

What’s new in AASTex 6.1?

Here are just a few of the new features and capabilities in the latest version:

  • Improved markup for authors, affiliations and collaborations
    Have an ORCID identifier? Now your author name can link to it. Juggling a lot of authors and affiliations? AASTex 6.1 offers automatic affiliation indexing, taking the burden off the manuscript preparer. Struggling to properly label members of collaborations in your author lists? There are new commands to help you do that more easily.
  • Options for layout styles
    Do you only use the default layout style when you prepare your manuscript? You have other options! In AASTex 6.1 a new style has been added, “modern”, which is designed for improved readability — especially on computers and mobile devices. You can now submit your manuscript in any of these available styles:

default: single column, single spaced, 10 pt font.
twocolumn: two column, single spaced, 10 pt font. This is the most compact layout style and representative of the final published version.
modern: one column, single spaced, 12 pt font, significantly wider margins.
preprint: one column, single spaced, 12 pt font.
preprint2: two column, single spaced, 12 pt font.
manuscript: one column, double spaced, 12 pt font.

  • New features for tables
    In addition to the new features for tables introduced in AASTex 6.0, now there are additional commands available to give authors flexibility in how long tables are handled, where tables appear on the page, and how they’re oriented.
  • revision tracking

    Example of how to track three different rounds of revisions to a manuscript.

    Better revision tracking control and editorial mark up
    AASTeX 6.0 introduced two methods to mark and track revision changes. Your feedback was used to improve the second method, which now lets you set whether or not to display different rounds of revisions. New commands have also been introduced so that you can document the publication history of your manuscript for preprints.

  • url support in the bibliography
    Been wishing you could include hyperlinks in your bibliography? The aasjournal.bst file has been updated to recognize the url field. If you include it, the reference in the compiled manuscript will be hyperlinked.

Where can you get more information?

Wishing for still more improvements? 

The AAS Publishing team appreciated your feedback on the last version of AASTex, and they’re happy to hear your comments on this one! You can contact them at aastex-help@aas.org with additional suggestions or ideas for the next iteration of AASTex.


Want to share astronomy by making a tour, interactive experience, or video using WorldWide Telescope? You should — and then you should enter it in the American Astronomical Society’s first WorldWide Telescope Competition!


WWT for Planet Nine

Visualization of Planet Nine’s hypothesized orbit, created using WWT as part of an article abstract. [WWT]

The AAS is hosting its first-ever competition for products created using WorldWide Telescope (WWT)! Since WWT joined the AAS family, we’ve seen it used for some great science communication by authors submitting video abstracts for their research articles (like this one), as well as some spectacular examples of interactive web-based experiences and awesome tours introducing people to astronomy concepts (like this one). We’d love to see what else people can come up with!

Entries are now being accepted in any of three categories: research, education, or planetarium.

In addition, there will be a special prize for the top WWT tour on information or safety on the upcoming 2017 solar eclipse.

WWT for planetariums

WWT can be used to produce planetarium shows as well! [WWT]


The competition is open to everyone: professional astronomers, students, and enthusiasts alike, with no age or nationality restrictions.


The deadline for entry is 5:00 pm on Friday, 16 December 2016. Winners will be notified by 31 December and recognized at the 229th AAS meeting (3–7 January 2017).


  1. To win prizes!
    There are prizes for the top three entries in each of the three categories, including Amazon gift cards, telescopes, and iPad minis, and there’s an additional prize for the top 2017 solar eclipse entry. There’s also an overall Grand Prize of an advanced goto mount and refractor telescope generously provided by Explore Scientific.
  2. To create an awesome education tool
    By using WWT to create a tour, interactive experience, or video, you’ll have a great visualization you can use to share your research or interesting astronomy at future conferences, talks, or outreach events. Winning entries will also gain broad additional exposure via the AAS — we can’t wait to share your products with our members and the public, in order to spread enthusiasm for astronomy and awe of our universe.


WWT Milky Way tour

An example of a WWT tour of the Milky Way. [WWT]

Already have a finished product you want to enter? Find out how to submit it here.

Don’t have a product yet, but have a plan and already know how to use WWT? If you have a Windows computer, you can download and install WWT here. Alternatively, go here to use WWT right in your web browser to create a tour!

No idea how to use WWT but want to try? You can check out this post for a few ideas, or tune in to upcoming live, online training workshops (and re-watch past ones). You can also go here for more information on using WWT.

Any final questions? Check out the official announcement for the 2016 AAS WorldWide Telescope Competition here. Happy creating!

Saturn Storm

Editor’s Note: This week we’re at the joint 48th meeting of the Division for Planetary Sciences (DPS) and 11th European Planetary Science Congress (EPSC) in Pasadena, California. Along with astrobites author Natasha Batalha, I will be writing updates on selected events at the meeting and posting at the end of each day. Follow along here or at astrobites.com! The usual posting schedule for AAS Nova will resume next week.

Welcome to Day 4 of the joint 48th meeting of the Division for Planetary Sciences (DPS) and 11th European Planetary Science Congress (EPSC) in Pasadena, California! Two astrobiters are attending this conference, and we will report highlights from each day here. If you’d like to see more timely updates during the day, we encourage you to search the #DPSEPSC hashtag!

Plenary Talks (by Susanna Kohler)

asteroid family

Artist’s illustration of how an asteroid family is created. Chaotic motion affects the orbits of such families of asteroids that form from catastrophic collisions. [NASA/JPL-Caltech]

Farinella Prize Lecture
Flavors of Chaos in the Asteroid Belt

This year’s Farinella Prize was awarded to Kleomenis Tsiganis (Aristotle University of Thessaloniki, Greece), for “timely and deep examples of applications of celestial mechanics to the natural bodies of the solar system”. Tsiganis is one of the developers of the Nice model, a model that describes the migration of Jupiter, Saturn, Uranus and Neptune during the early phases of the solar system’s evolution to their currently observed positions.

Tsiganis’s prize lecture described how we can combine our knowledge of chaotic dynamics with observations to understand several interesting features of the asteroid belt, such as mean-motion resonances of asteroids, or the behavior of asteroid families (produced when a collision disrupts a parent body into fragments).

Harold C. Urey Prize Lecture
In for the Long Haul: Exploring Atmospheric Cycles on the Giant Planets

This year’s Harold C. Urey Prize for outstanding achievement in planetary research by a young scientist was awarded to Leigh Fletcher (University of Leicester), in recognition of his ground-breaking research in understanding physical and chemical processes in the atmospheres of the outer planets.

Why study the atmospheres of the giant planets? These atmospheres, Fletcher argued, are the heatbeats of the giant worlds. We are just now at a stage where we are able to measure and better understand the way that giant planet atmospheres change, shift, and oscillate on short and long timescales — and it’s an exciting time!

vanishing band

Jupiter’s prominent southern belt mysteriously vanished in 2010, before later reappearing. Ground-based observations revealed that a plume from deeper in the atmosphere may have been instrumental in reviving the belt. [ESA/Hubble]

Fletcher’s lecture provided an overview of the different cycles we’ve been able to study in the atmospheres of giant planets. These include:

  1. Seasonal evolution
  2. Stratospheric oscillations
  3. Belt/zone upheavals
  4. Storm eruptions

An example: the clouding out of one of Jupiter’s most prominent belts. In 2010 we watched Jupiter’s South Equatorial Belt turn white as it was clouded out; a few months later the clouds dissipated and it returned to normal. High-resolution ground-based observations revealed a plume punching up from lower layers to deliver material high into Jupiter’s tropopause before the belt returned. This activity likely helped to clear up the clouds and revive the belt.

saturn storm

Stunning Cassini observations showing a false-color mosaic of a giant storm that raged on Saturn in 2010/2011. [NASA/JPL-Caltech/Space Science Institute]

Another example: Saturnian storms. Roughly once every Saturnian year, a large storm erupts on the planet. In 2010-2011, Cassini took some spectacular images of an enormous storm that briefly formed the largest non-polar vortex in the solar system! Observations from Cassini were used to understand how energy was transported through the atmosphere in this storm.

Fletcher concluded by discussing what’s next for giant-planet atmosphere studies. He expressed his fervent hope that a dedicated mission to our outer ice-giant planets — which haven’t been visited since Voyager 2’s flyby in the late 1980s — would be completed within the next half century. He argued that studying the atmospheres of Uranus and Neptune is important because they represent a missing link between giant planet atmospheres and smaller terrestrial atmospheres. Plus these planets have plenty of satellites, so a mission to the ice giants would be able to find many targets to make everybody happy!

Until then, we can look forward to continued discoveries with ground-based telescopes, upcoming observations with JWST, and future programs, like a return to Jupiter with JUICE and NASA’s Europa mission.

The Ancient Habitability of Gale Crater, Mars, after Four Years of Exploration by Curiosity

In the final plenary of the meeting, Ashwin Vasavada (Project Scientist for Curiosity, JPL) and Sanjeev Gupta (Imperial College London) gave a tag-team overview of what we’ve learned about the past habitability of Mars from observations by the Curiosity rover.

Curiosity Trek

Context for Curiosity’s journey. The path it’s already traversed is shown in yellow. Green is where it’s headed. [NASA/JPL/T.Reyes]

Vasavada opened the talk by mentioning that Curiosity has recently drilled its 15th hole in the surface of Mars! When the rover drills samples from rocks, the resulting powder is analyzed by its CheMin instrument, allowing us to determine the exact mineral composition of the sample. This has revealed a lot of information about the terrain that Curiosity has been traveling through.

Vasavada took us on a tour of the first part of the rover’s journey within Gale crater as it has made its way to Mount Sharp. The crater is 150km wide, and the layers of rock around Mount Sharp likely contain a record spanning several hundred million years during a period of dramatic climate evolution in Mars’s early history. Almost immediately after landing, Curiosity was able to probe that history when it drove across an ancient streambed littered with rounded pebbles, providing unmistakable evidence that Mars once had flowing water on its surface.

Not long after that point, the rover arrived at Yellowknife Bay, where it took its first mineralogical samples and gathered data indicating that the region was likely an ancient lakebed. Curiosity’s observations suggest that ancient Mars was capable of supporting life: it appears to have had liquid water with a neutral pH and low salinity, key elements and nutrients necessary for life, and energy for metabolism.

Gale crater

Curiosity’s images of what was likely once an ancient lake bed on Mars. [NASA/JPL-Caltech/MSSS]

 Gupta took over describing Curiosity’s ongoing journey to the base of Mount Sharp. The observations that Curiosity has made along the way have provided additional signs of past lakes and groundwater systems — not just at one point in Mars’s history, but in fact active hydrological cycles spanning millions to tens of millions of years! This suggests that habitable conditions may have existed on Mars for quite some time in the past.

Curiosity still has plenty of mission time and a long journey ahead of it, so it seems likely that we can count on many more revelations from this intrepid little rover.

South Pole

Editor’s Note: This week we’re at the joint 48th meeting of the Division for Planetary Sciences (DPS) and 11th European Planetary Science Congress (EPSC) in Pasadena, California. Along with astrobites author Natasha Batalha, I will be writing updates on selected events at the meeting and posting at the end of each day. Follow along here or at astrobites.com! The usual posting schedule for AAS Nova will resume next week.

Welcome to Day 3 of the joint 48th meeting of the Division for Planetary Sciences (DPS) and 11th European Planetary Science Congress (EPSC) in Pasadena, California! Two astrobiters are attending this conference, and we will report highlights from each day here. If you’d like to see more timely updates during the day, we encourage you to search the #DPSEPSC hashtag!

Third Press Conference: Updates on ExoMars and Planet Nine (by Susanna Kohler)

Did you follow ExoMars’s Schiaparelli module as it attempted to land on Mars’s surface this morning? Today’s first press conference opened with an overview of the latest news from the attempt, given by Olivier Witasse (ESA). Witasse summarized the first phase of the mission, in which ExoMars’s Trace Gas Orbiter (TGO) enters in orbit around Mars and Schiaparelli attempts its landing. The primary goal of this phase is to test the technology for an entry, descent, and landing of a payload on Mars, but the mission has secondary science goals of studying the Martian atmosphere and conducting surface environment measurements.


Schiaparelli’s planned descent and landing timeline. Click to read! [ESA/ATG medialab]

Schiaparelli’s anticipated landing on Mars was a complex, 6-minute process. Witasse informed us that, while the team received confirmation during this time of key milestones like the parachute deployment, contact was cut off before the final landing. As images from the lander weren’t supposed to be sent until after the landing, we don’t have more information from the lander itself; we’re currently waiting for telemetry from the Mars Reconnaissance Orbiter and info from TGO to find out what Schiaparelli’s status is. Witasse emphasized that the mission is “not nominal”, but it’s too soon to tell what happened.

Meanwhile, however, we can focus on the very successful insertion of TGO into orbit! The next speaker, Ann Carine Vandaele (Royal Belgian Institute for Space Aeronomy), discussed some of the science that will be done with TGO. In particular, TGO’s NOMAD instrument will measure the chemical composition of the atmosphere, Mars climatology and seasonal cycles, and help us to build models of the planet’s atmosphere. TGO’s timeline begins with 2 orbits for calibration, and then the next year will be spent aerobraking to get the spacecraft into its final circular orbit around Mars. The official science mission begins after that point!

Artist's illustration of the hypothetical Planet Nine, a massive planet lurking in the outskirts of our solar system. [Caltech/Robert Hurt]

Artist’s illustration of the hypothetical Planet Nine, a massive planet lurking in the outskirts of our solar system. [Caltech/Robert Hurt]

Next, the focus of the press conference shifted to the hypothetical Planet Nine. Renu Malhotra talked about how we’ve further constrained the massive planet’s location based on the orbits of trans-Neptunian objects (TNOs). The longest-period TNOs all have periods that are integer multiples of each other. If we assume that’s because they’re in resonance with a distant, massive planet, we can get constraints on the orbit of that planet. Malhotra and collaborators find that a planet on an orbit with a ~665 AU semi-major axis could produce resonant TNO orbits consistent with what we see. You can read more about this here or check out the press release here.

Finally, Mike Brown spoke about one of the latest discoveries he and his team have made about the possible effects of Planet Nine on the solar system. Brown pointed out that the Sun’s axis is tilted by about 6° with respect to the axis of the solar system. If everything formed from the same protostellar nebula, why the misalignment? He showed that the presence of a distant, massive planet on an inclined orbit can actually create that misalignment over time, as a result of the planet’s large mass and long lever arm. The tug of the planet’s gravitational force effectively tilts the solar system over its lifetime! Brown’s models show that the predicted orbit and mass of Planet Nine are consistent with the 6° tilt that we see: chalk this up as one more piece of evidence supporting Planet Nine’s existence. The press release can be found here.

Fourth Press Conference: Updates from the Juno Mission at Jupiter (by Susanna Kohler)

In the second press conference of the day, we received updates on the mission status and science outcomes of the Juno mission to Jupiter. Juno, launched in 2011, is the second of NASA’s New Frontiers programs (the first was New Horizons mission to Pluto). It arrived at Jupiter on July 4th of this year, and it’s currently in a 53.4-day highly elliptical orbit around the planet.


Artist’s concept of the Juno mission to Jupiter. [NASA/JPL-Caltech]

David Schurr, the deputy director of NASA’s Planetary Science Division, opened the conference with some bad news: the Juno spacecraft went into safe mode at 10:47 PDT last night, just 13 hours from its closest approach to Jupiter in its orbit. This means that the team wasn’t able to do the science pass they had planned during this second “perijove” flyby of the mission.

Scott Bolton, Juno’s PI, provided more information about Juno’s current state. Bolton’s take on the recent events was calm: though the spacecraft evidently encountered something unexpected, it responded exactly how it was supposed to. Juno is currently healthy and in no danger, and it will continue on its current 53.4-day orbit while scientists analyze what triggered the safe-mode entry.

This glitch follows on the heels of another, unrelated delay: last week the decision was made to postpone a burn of Juno’s engines to reduce its period from 53.4 days to 14 days. This “period reduction maneuver” was put off when unexpected behavior was discovered with a pair of valves operating the propulsion system. The team is currently analyzing this as well, to determine whether it will be safe to fire the engines on Juno’s next pass. When asked what he considered to be the worst-case scenario for the mission, Bolton drew laughs with his response: “I have to be patient and get the science slowly.” He elaborated that Juno’s current orbit will produce exactly the same science results as the planned 14-day orbit, just a bit slower!

Bolton then walked us through a little of what we’ve learned from Juno so far. Details from this are discussed below, in Natasha’s summary of Bolton’s plenary talk later in the afternoon.


This image of the cyclones at Jupiter’s south pole was processed starting from JunoCam’s raw data, which is publicly available. [NASA/SwRI/MSSS/Roman Tkachenko]

Next Candice Hansen, JunoCam imaging scientist from the Planetary Science Institute, told us about the public outreach camera mounted on Juno. This camera was designed to engage the public with the Juno mission, but it turns out it’ll also produce lots of interesting science! Already, we have some spectacular images of Jupiter’s south pole (the first time this has been imaged) which reveal the region’s cloud structure. In particular, the pole is swirling with cyclonic storms, and the presence of one on the terminator provides us with new 3D information about the dynamics of the atmosphere. Analysis of this storm shows that it’s a whopping 7,000 km (more than half the size of Earth) across and towers ~85 km vertically.

The public has several ways they can engage with JunoCam. Public input will drive the target selection for the camera, with proposals, discussion, and eventual voting planned to be enabled late this year or early next year. And all images taken with JunoCam are uploaded in raw format for anyone to download, process, and upload their final images. This has already resulted in some spectacular public-produced images using JunoCam data, viewable here, and should continue to result in stunning visuals and exciting science in the future!

Plenary Talks (by Natasha Batalha)

Early Results from Juno Mission at Jupiter: Scott Bolton

Dr. Scott Bolton followed up his press conference by giving a plenary talk on Juno’s early science results. Though Juno is currently in safe mode, the team is continuing to analyze data from the close flyby from August 27. Dr. Bolton started his talk by showing a new brightness map of the northern aurora. Just from this first map the team is “seeing things we did not expect”. Both the aurora and the magnetic field are much stronger than models previously suggested. The team is working on creating new models to match their preliminary observations. Gravity science also is forcing theorists to revisit their models and on December 11th, we will have a factor of 20 improvement in this data.

Preliminary Juno data from the Microwave Radiometer instrument shows the bands we see on the surface of Jupiter, extend down to depths of ~200 bars (300-400 km).

Preliminary Juno data from the Microwave Radiometer instrument shows the bands we see on the surface of Jupiter, extend down to depths of ~200 bars (300-400 km). Image credit: NASA/JPL

Next, Dr. Bolton showed the audience observations taken with Juno’s Microwave Radiometer instrument (MWR). MWR’s mission is to understand and characterize the interior layers of Jupiter. There are six channels ranging from 1-50 cm wavelength which will each be able to penetrate down to a pressure of 200 bars (400 km). Already, the team can tell that the large banding structure that we see on the surface extends down to ~300-400 km.

Juno’s main mission is to gain understanding of the Solar System’s beginnings by revealing the origin and evolution of Jupiter. Despite the current difficulties the team is having, Dr. Bolton ended by reassuring the audience that the team will still be able to complete all the goals it sought out at the start.

Dawn at Ceres: Michael Toplis, Cristina De Sanctis

After Dawn launched in September of 2007, it spent four years focused on studying Vesta, the second most massive asteroid. Since February 2015, it has been on course to study Ceres. Dr. Michael Toplis and Dr. Cristina De Sanctis tag-teamed the second plenary to reveal preliminary studies concerning Ceres.

Like with Juno, Dawn is also trying to measure the gravity field of Ceres. Doing so will give us insights into whether or not Ceres is homogenous (is it a solid cue ball or a layered onion?). New gravity data has already ruled out a homogenous mixture. Instead, the Dawn team suggests that Ceres has a weak interior and that water and other light materials may have been partially separated from the rock. This layering is much weaker than the layering you find in Earth’s interior or even our very own Moon.

A photo of Ahuna Mons, the only mountain on the entire surface of Ceres. Ahuna Mons is only 3 miles high and it is likely volcanic in origin.

A photo of Ahuna Mons, the only mountain on the entire surface of Ceres. Ahuna Mons is only 3 miles high and it is likely volcanic in origin. Image Credit: NASA/JPL

The Dawn team has also been looking carefully at the surface of Ceres. Right off the bat it is easy to see that Ceres is highly cratered, with one small exception: Ahuna Mons, a small, 3-mile-high mountain discovered by the Dawn team. Ahuna Mons is the only mountain on the entire object that might have been volcanic in origin. Along with the heavy cratering, Dr. Cristina De Sanctis discussed the discovery of phyllosilicates all over Ceres’ surface. Phyllosilicates are rich in magnesium with some ammonium in their crystalline structure. The fact that these are found all over Ceres’ surface means that the surface has been altered by some interaction with water.

The team concluded by rounding up what all the information about Ceres is pointing to. It is possible that either Ceres formed in the trans-Neptune disk before it was implanted into the main belt, OR Ceres formed closer to its present position by accreting material that drifted from out at greater distances. More data will start to yield a better image of what is going on with this interesting object.


Editor’s Note: This week we’re at the joint 48th meeting of the Division for Planetary Sciences (DPS) and 11th European Planetary Science Congress (EPSC) in Pasadena, California. Along with astrobites author Natasha Batalha, I will be writing updates on selected events at the meeting and posting at the end of each day. Follow along here or at astrobites.com! The usual posting schedule for AAS Nova will resume next week.

Welcome to Day 2 of the joint 48th meeting of the Division for Planetary Sciences (DPS) and 11th European Planetary Science Congress (EPSC) in Pasadena, California! Two astrobiters are attending this conference, and we will report highlights from each day here. If you’d like to see more timely updates during the day, we encourage you to search the #DPSEPSC hashtag!

Town Hall: Observing the Solar System with JWST (by Susanna Kohler)

The James Webb Space Telescope, the upcoming infrared space telescope with an unprecedented 6.5-m mirror, is highly anticipated for the new view it will give us of the universe. But not all of JWST’s observations will be of distant stars and galaxies — the telescope is fully capable of making detections much closer to home.

Though JWST won’t be able to observe in the inner solar system, it will be able to examine planets, satellites, rings, asteroids, Kuiper belt objects, and comets located at the distance of Mars and outward. Here are just a few of the solar-system observations the planetary community has proposed that JWST will be well-suited to make.

  1. Observations of Mars
    JWST can examine Mars’s atmosphere globally, allowing us to learn about the planet’s past habitability, its current water sources, and the chemical stability of its atmosphere.
  2. Observations of Asteroids and Near-Earth Objects
    JWST can provide imaging and spectroscopy that will allow us to learn about the albedo, size, surface roughness, thermal inertia, and surface composition of small bodies in the solar system.
  3. Observations of the Giant Planets
    JWST can examine auroral processes, track atmospheric dynamics after impact events on the planets, and investigate major storm systems.
  4. Observations of Rings and Small Satellites
    JWST can discover new rings and moons, probe ring structure with occultations, probe the composition of the rings with spectroscopy, and investigate how these systems evolve over time.
  5. Observations of Titan
    JWST can provide long-term monitoring of the changing seasons on Saturn’s moon, investigating the evolution of its atmospheric composition, clouds and hazes, and surface temperatures and features.
  6. Observations of Dwarf Planets
    JWST can create detailed maps of the compositions of distant dwarf planets beyond the orbit of Neptune — in particular, those with significant inventories of volatile ices on their surfaces.
A nerve-wracking moment wherein JWST science instruments are lifted by crane above the mirror, and both are suspended face-down over the clean-room floor, as the observatory is assembled. [NASA/Chris Gunn]

A nerve-wracking moment wherein JWST science instruments are lifted by crane above the mirror, and both are suspended face-down over the clean-room floor as the observatory is assembled. [NASA/Chris Gunn]

In today’s town hall, JWST Deputy Project Scientist for Planetary Science Stefanie Milam (NASA/GSFC) provided an overview of JWST, discussed how it could be used for planetary science, and gave us an update on the telescope’s status.

JWST’s progress is grouped into yearly themes: 2013’s was instrument integration, 2014’s was manufacturing of the spacecraft, 2015’s was assembly of the mirror, and 2016’s has been assembly of the observatory. At this point the mirrors and instruments are installed, and the assembly of JWST is nearing completion! 2017 will be a year of testing all the components of the telescope at the Johnson Space Center, in preparation for a 2018 launch.

Next up in the town hall, STScI Solar System Science Lead John Stansberry provided us with details of JWST’s observing modes and capabilities, and discussed what they mean for astronomers interested in proposing observing time on the telescope, particularly for planetary observations. Will Grundy (Lowell Observatory) then discussed the use of JWST for high-resolution imaging. Ultimately JWST will have roughly comparable angular resolution to Hubble, but in infrared wavelengths instead of optical. The depth and detail that this will provide should make for both spectacular images and exciting new science!


An old-school stereoscopic slide viewer — useful for those of us who are terrible at free-viewing stereoscopic images! [ThePassenger]

Finally, Joel Green (STScI) pitched an idea to use both JWST and Hubble for combined observations of the same targets. The two telescopes, which overlap in observing wavelength between 0.7–1.6 µm, are separated by a 1.5 million km baseline. This means that, when used together, they could produce stereoscopic images similar to the “magic eye” pictures many of us have spent hours staring at cross-eyed!

Why is this better than taking two images 6 months apart with the same telescope, making use of annual parallax to create a baseline? The advantage to using both JWST and Hubble together is simultaneity: if Hubble and JWST make their observations at the same time, we can create stereoscopic images of transient events. Potential cases where this is useful include comet/asteroid activity, cometary collisions, and cloud/storm features on giant planets.

Second Press Conference (by Natasha Batalha)

Today’s press conference all centered around New Horizons’s mission results. Before the speakers began, New Horizons’s Principal Investigator, Alan Stern, said a few words. To give you an idea of what it has been like for the team, Dr. Stern said that during it all they “felt like doctors triaging patients.” The full press release can be found here.

Pluto’s Extreme Surface Reflectance Variations: Bonnie Buratti (NASA Jet Propulsion Laboratory) 

One of the major goals of the New Horizons mission was to answer the question of how reflective Pluto really is and how exactly it scatters light. Dr. Bonnie Buratti was excited to show a map of the albedo (reflectivity) of Pluto. The map shows a region of very high (nearly perfect) reflectivity right in the middle of Sputnik Planitia, a large geological feature on Pluto. Dr. Buratti and her team were interested in knowing what, if any, other objects in the Solar System exhibit this same behavior. They found that the only other system with a similar large range in reflectivity was Iapetus, one of Saturn’s moons. They also looked at objects in the Kuiper belt and found one object, Eris, with regions with nearly perfect reflectivity. Dr. Buratti and her team are excited because they think this might mean Eris is geologically active, like Pluto.

Possible Clouds on Pluto: Alan Stern (Southwest Research Institute)

Moving from the surface of Pluto to the atmosphere, Dr. Alan Stern continued to talk about the possibility of clouds on Pluto. Clouds are common across nearly all the planets in our Solar System: Venus, Earth, Mars, Jupiter, etc. The New Horizons team had previously announced that Pluto’s atmosphere was enveloped in haze layers. This detection posed a number of mysteries. The hazes appeared very high in the sky and the team is still unsure how they have formed. These hazes are only about 25% optically thick, however — which means that to date, clouds, which are much more optically thick, have not been detected. Today, Dr. Stern announced the detection of 7 possible small clouds lying very low near the surface of Pluto. All together, these 7 clouds take up less than 1% the surface area of Pluto, meaning that generally, Pluto is cloud-free. In the future, it will be interesting to understand what these potential clouds are made of, and if they aren’t clouds, what we are in fact seeing.

Seven possible clouds in Pluto's atmosphere. Image credit: NASA/JHUAPL/SwRI

Seven possible clouds in Pluto’s atmosphere. [NASA/JHUAPL/SwRI]

Landslides on Charon: Ross Beyer (NASA Ames Research Center) 

Straying away from Pluto all together, Dr. Ross Beyer, discussed the discovery of landslides on Pluto’s largest moon, Charon. This is peculiar because the New Horizons data shows that Pluto is void of any landslides. And as Dr. Stern discussed in his plenary talk yesterday, Charon is geologically inactive, as compared to Pluto. So why does Charon have these features, but not Pluto? In fact, these are the first landslides we’ve seen this far away from the Sun. We don’t know what material the landslides are made of or why they are forming without a dedicated orbiter. It will be very interesting for the team to see if they can detect these landslides anywhere else in the Kuiper Belt.

Landslides on Charon, discovered by New Horizons. Image credit: NASA/JHUAPL/SwRI

Landslides on Charon, discovered by New Horizons. [NASA/JHUAPL/SwRI]

Hubble Reveals that New Horizons Flyby Target 2014 MU69 is Red: Susan Benecchi/Amanda Zangari (Planetary Science Institute) 

The last press release was given by Dr. Amanda Zangari, a post-doctoral researcher at Southwest Research Institute, who was filling in for Dr. Susan Benecchi. The New Horizons mission has completed its initial mission requirements and has already started preparing for its extended mission. During its extended mission, the main flyby target is 2014 MU69. This object was discovered by the Hubble Space Telescope and is located in what is called the “cold classical Kuiper Belt”. The cold classical Kuiper Belt is a very old primordial region where none of the objects are interacting with Neptune and all of the objects have very low inclinations. This leads scientists to think that 2014 MU69 is one of the ancient building blocks of the planets in our Solar System. One method of verifying this (before actually going there) is to measure the color of the object. Data from Hubble reveals that this object may in fact be part of the primordial region in the Kuiper Belt. Therefore, New Horizons will be heading there and on January 1, 2019 we will know for sure!


MAVEN clouds cover

Editor’s Note: This week we’re at the joint 48th meeting of the Division for Planetary Sciences (DPS) and 11th European Planetary Science Congress (EPSC) in Pasadena, California. Along with astrobites author Natasha Batalha, I will be writing updates on selected events at the meeting and posting at the end of each day. Follow along here or at astrobites.com! The usual posting schedule for AAS Nova will resume next week.

Come visit us at our poster with AAS Nova! #419.02

Come visit us at our poster with AAS Nova! #419.02

This week Astrobites will be reporting from the joint 48th meeting of the Division for Planetary Sciences (DPS) and 11th European Planetary Science Congress (EPSC) in Pasadena, California! Two astrobiters are attending this conference, and we will report highlights from each day here on astrobites. If you’d like to see more timely updates during the day, we encourage you to search the #DPSEPSC hashtag!

Monday morning was the official start of the meeting. We’ve got a joint poster for Astrobites/AAS Nova at poster #419.02 in the exhibit hall — come stop by to chat (and for stickers!). For those of you who can’t be here in person, here’s an update on the plenaries and press conferences from the first day of DPS this year.

Jonathan Eberhart Planetary Sciences Journalism Award (by Natasha Batalha)

The meeting kicked off with the presentation of the Jonathan Eberhart Planetary Sciences Journalism Award, which was awarded to Nadia Drake. Nadia has been an instrumental figure in space sciences communication. She’s reported on everything from other worlds to exploding stars, to the fabric of the universe. Her work is an inspiration to many of us here at Astrobites. Be sure to check out her stuff!

Artist’s impression of Rosetta, Philae, and Comet 67P. [ESA/ATG medialab; ESA/Rosetta/NavCam]

Artist’s impression of Rosetta, Philae, and Comet 67P. [ESA/ATG medialab; ESA/Rosetta/NavCam]

Plenaries (by Natasha Batalha)

The Rosetta Mission: Matt Taylor

The Rosetta Mission gathered huge media attention in November 2014 when its robotic lander, Philae, landed on comet 67P/Churyumov-Gerasimenko. Almost two years later, Matt Taylor stands on the stage of Ballroom D to report on the mission’s current status. Rosetta was given its name because, like the Rosetta stone, the spacecraft is a key to deciphering the origin of the Solar System. Dr. Taylor begins by showing just a small fraction of the copious amounts of images that were gathered. Comets, which were previously thought of as icy dust balls, are now known to be geologically complex places, he discusses. Rosetta has paved a completely new field of cometary geology and they’ve still only analyzed about 5% of all the data that was collected.

“Now that we have the whole data set we are revising our numbers to get a sense of the whole picture.” 

From measurements of the molecular oxygen, combined with the detection of nitrogen, noble gases and the D/H ratio in the water, we know that this comet was born in a very cold region in the protoplanetary nebula, far from the Sun. Meaning, this comet might offer us a glimpse of what the building blocks of planets and moons may have been. The D/H ratio also tells us that Earth’s water was likely not delivered from comets, since the D/H values from the comet do not match those from Earth’s oceans. But from looking at the data taken from Noble gasses, it’s possible that other complex material may have been.

In late September of this year, the Rosetta mission concluded its mission as planned with a controlled impact onto the comet. On decent they were able to successfully study the comet’s gas, dust and plasma very close to the surface.

“We’ve got the Rosetta stone, now we have decades or work to do to analyze the data.”

The Latest Views of Venus as Observed by the Japanese Orbiter: Takehiko Satoh

Artist’s illustration of the “Akatsuki” mission to Venus. [JAXA]

Artist’s illustration of the “Akatsuki” mission to Venus. [JAXA]

Just one year ago, the Japanese Aerospace Exploration Agency held a press conference to announce the successful arrival of Akatsuki, Japan’s very first planetary orbiter, into a Venus orbit. Dr. Takehiko Satoh is here to today give an overview of the mission. Understanding the atmosphere of Venus has been difficult because of the thick cloud decks that inhibit our ability to see down to the surface.

Dr. Satoh explained that Akatsuki’s mission is to understand and detail the atmospheric dynamics of Venus, get a 3-D view of wind fields and describe any spatial and temporal variations in the atmosphere. This includes answering the long standing question of whether or not Venus has lightning and/or volcanism. Akatsuki is also the first and only meteorological satellite orbiting a planet other than the Earth, which will lead to some very interesting data in the near future.

Unfortunately we will have to wait a while to answer all of those questions considering first light images were taken in December of 2015 and regular observations started on April 1, 2016. Nevertheless, Dr. Satoh was able to show some very exciting preliminary studies:

  1. They visualized the cloud motion and variations of minor gases on Venus by acquiring multi-wavelength images continuously through time.
  2. They looked at fine scale features in order to attempt to detect lightning in the night (none have been detected so far).
  3. They detected SO2 absorption and also detected an unknown absorber at 365 nm! Dr. Satoh poses the questions, what is actually there? And how are they related to atmospheric dynamics and cloud formation?
  4. They mapped thermal emission from the surface and detected an E-W elongated low temperature region.

Dr. Satoh ended by explaining that their team has a lot of work to do in order to fully synthesize all of these discoveries but that in the near future we should expect a lot more interesting science!!

New Horizons

Illustration of the New Horizons spacecraft’s encounter with the Pluto–Charon system. [NASA/JHU APL/SwRI/Steve Gribben]

New Horizons: Overview of Results From and Plans After the Exploration of the Pluto System: S.A. Stern

The last plenary talk was given by Dr. Alan Stern who gave an exciting overview of the New Horizons mission. He started by showing the massive scientific payload that allowed New Horizons to accomplish, what he says is as much science as several Mars missions, combined.  In fact, the mission met all of its science objectives, published over 40 studies and presented findings at over 200 meetings. New Horizons also just recently won and initiated its extend mission, which warrants a massive congratulations to the New Horizon’s team! So what were the major scientific studies you should be on the lookout for?

Dr. Stern says the most surprising finding (for him) was the stark difference between Pluto and Charon. Pluto and Charon have similar densities and sizes and New Horizons also showed that there was, at some point, some degree of atmospheric transfer from Pluto to Charon. Besides that though, everything else (surface & atmosphere) about the two bodies are wildly different. Pluto has a complex and active surface. Some terrains on Pluto are brand new, while others formed over four billion years ago. Pluto also has a complex atmosphere, which contains molecules such as water, methane and nitrogen. They also found that these molecules are not uniformly distributed around the planet. Charon, on the other hand, has no detectable atmosphere — or, if it does, it is smaller than the atmosphere of our very own Moon. Charon’s terrains are also all older than four billion years old, with no new activity.

Dr. Stern says they is still a lot of work to be done to answer exactly how these planets ended up with such different properties. And THIS Sunday all the New Horizons data will be available, so you too can download it and start to analyze some of these peculiar features.

First Press Conference (by Susanna Kohler)

Idunn Mons

An elevation model of Venus’s volcano Idunn Mons. [ESA/DLR]

The first press conference of the meeting opened with a talk by Piero D’Incecco (German Aerospace Center), who discussed evidence for recently active lava flows on Venus. Using clever numerical modeling techniques combined with observations from ESA’s Venus Express mission, D’Incecco and collaborators have looked through Venus’s thick cloud cover in infrared wavelengths to detect several lava flows from the top and eastern flank of the volcano Idunn Mons, which is located in Venus’s southern hemisphere. The team’s work has focused on identifying the location and extent of these flows to learn more about volcanism on the surface of Earth’s “twin” planet. The full press release can be found here.

Next up was Nick Schneider (Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder), who spoke about the most recent results from the MAVEN mission to Mars. Three interesting findings have come from MAVEN’s unprecedented ultraviolet coverage of Mars:

  1. Observations of “nightglow” emission on Mars’s night side, as its atmosphere emits light in UV due to chemical reactions that start on its day side. These observations reveal information about Mar’s high-altitude winds.
  2. Evidence that ozone in Mars’s atmosphere accumulates inside a vortex at Mars’s pole during the winter time — again, providing critical information about the global circulation about Mars’s atmosphere.
  3. Beautiful observations of afternoon cloud formation over Mars’s four giant volcanos, suggesting cloud formation happens there in a similar way to cloud formation over Earth’s mountain ranges.

The full press release can be found here.

MAVEN clouds

Images from MAVEN’s Imaging UltraViolet Spectrograph demonstrating the rapid cloud formation in Mar’s atmosphere. These images were taken over the span of ~7 hours. [NASA/MAVEN/University of Colorado]

Next came a series of three talks on the intriguing comet 67P/Churyumov-Gerasimenko. The first was by Mattia Galiazzo (Western University, Canada), on a study of the origin of comet 67P. Using computer simulations, Galiazzo and collaborators modeled the comet’s most probable orbit in order to discover where the body came from. They find that 67P is likely relatively new to the inner parts of our solar system, having lived in the scattered disk — the outskirts of the solar system — for millions of years. Perturbations by other bodies in our solar system then tweaked the comet’s orbit until it arrived in the inner region only ~10,000 years ago. The full press release can be found here.

67P outburst

A collimated outburst from Comet 67P, as captured by Rosetta’s OSIRIS camera. [ESA/Rosetta/OSIRIS]

Stubbe Hvidd (German Aerospace Center) next gave a dynamic talk on 67P as the “creaking and cracking comet”. Hvidd used high-resolution imaging of the comet to demonstrate that its surface has several recently-formed cracks — especially in its neck, the narrow region between its two lobes — that indicate it’s under stress as it hurtles through space in its orbit. Hvidd and collaborators have modeled the forces on the comet to show that its rotation and activity are creating stresses that will likely change the shape of the comet over the next several hundred years.

Finally, Jordan Steckloff (Planetary Science Institute) wrapped things up with a discussion of outbursts from comets like 67P. Steckloff suggests that, rather than being caused by internal pressure like geysers on Earth, comet outbursts might the result of avalanches on their surfaces. He showed that material sliding down the comet’s surface to a local low-potential point can enter a region that is sublimating due to sunlight exposure. As the granular materials slide into this region, they can be blown off in a tightly collimated plume that matches observations of comet outbursts. The full press release can be found here.


Next week we’ll be reporting from the joint 48th meeting of the Division for Planetary Sciences (DPS) and 11th European Planetary Science Congress (EPSC). Planetary science articles are a large component of the work featured in AAS journals; nearly 400 planetary science articles were published in AAS journals in 2015 alone, and these have already gathered almost 2400 citations.

In the lead-up to next week’s meeting, we’d like to introduce Melissa McGrath, our new Lead Editor for the Solar System, Exoplanets, and Astrobiology corridor. Melissa is a Senior Scientist at the SETI Institute. Her impressive list of former positions includes Deputy Director of NASA’s Science Mission Directorate’s Planetary Science Division, and Chair of the AAS’s Division for Planetary Sciences.

* * * * *


Artist’s impression of the planned Jupiter Icy moons Explorer (JUICE) mission that will study Ganymede, Callisto, and Europa. [NASA/JPL]

Tell me about your field of research and some of your current projects.

I’ve worked on a wide variety of things, primarily planet and satellites atmospheres, particularly the Galilean satellites of Jupiter. I’m currently involved in several Hubble Space Telescope observing programs, and I’m also a co-investigator on three instruments flying on missions to Europa and Ganymede.

What is your history with the AAS Journals?

I started out as a Scientific Editor for AJ in 2009 handling the solar system papers. I then was added to both ApJ Letters and ApJ as a Scientific Editor. Now I am one of the six Lead Editors for AAS Journals (ApJ + AJ), handling solar system, exoplanets, and astrobiology papers.

What do you anticipate will be some of the most exciting topics presented on at the DPS/EPSC meeting next week?

Planet Nine, results from the New Horizons mission to Pluto, the first results from the Juno mission, and the latest work on exoplanets, to name just a few!

What do you consider to be some of the biggest open questions in the field of planetary science today?

Is there life beyond Earth in the solar system? How did our own solar system form?

exoplanet atmosphere

Artist’s impression of the atmosphere of a rocky exoplanet. [NASA/Dana Berry (SkyWorks)]

Your journal corridor, “Solar System, Exoplanets, and Astrobiology”, encompasses a broad range of topics. How do you feel that these different areas of research all fit together?

They are tied closely together by the search for life beyond Earth, by understanding how planetary systems form and evolve. They are also tied closely together by the study of planetary atmospheres, both within our own solar system and in exoplanets.

What do you think makes for a well-authored paper?

The most fundamental thing is having a new result and explaining it in a clear, concise, and convincing fashion.

Is there anything else you’d like to share about the publishing process with potential authors?

I’m continually impressed with how professional the whole process of peer review and publishing of new science results is. Both the authors and referees do an outstanding job, and almost without exception they are both geared to making high-quality science research available to the community in a positive, success-oriented process. That makes being an Editor a fun job for the most part.

* * * * *

Look for the AAS Publishing team at DPS 48/EPSC 11 next week — we’ll be in the exhibit hall at Booth #101! And if you can’t be at the meeting, be sure to check back on this site all next week, as AAS Nova and Astrobites will be working together to bring you daily updates from the meeting.

illustration of a spacecraft in front of the milky way, with multiple patches identified along a sinusoidal curve.

Editor’s Note: Last week we were at the 228th AAS Meeting in San Diego, CA. Here is a final post about selected events on the last day of the meeting, written by authors from astrobites.com, a grad-student collaborative project with which we recently announced a new partnership! Starting in July, keep an eye out for astrobites posts at AAS Nova in between Highlights (i.e., on Tuesdays and Thursdays). We’re excited to be working together to bring you more recent astronomy research from AAS journals!

Extrasolar Planets: Detection (by Leonardo dos Santos)

Thursday’s first session on exoplanets was about detecting these distant worlds, and the opening talk was given by Robert Siverd (Las Cumbres Observatory). He describes the NRES, a network of spectrographs that will look for exoplanets using the radial velocity method. One of the coolest aspects of this instrument is that it will feature an “on the fly” scheduling system that will perform observations as efficiently as possible. The spectrograph is still being tested, but a unit will be deployed at CTIO later this year.

Measuring the depths of transits and eclipses in Spitzer has been problematic in the past, since the Spitzer instrument IRAC (InfraRed Array Camera) has a non-uniform response in its detector’s pixels. But, as reported by James Ingalls (Spitzer Science Center, Caltech), observers are circumventing this issue by using what they call the staring mode (avoiding large pointing jumps) and an algorithm to pick “sweet spot” pixels. Moreover, the results from the IRAC Data Challenge are helping to better understand its behavior. Giuseppe Morello (University College London), on the other hand, explained how his research group gets rid of instrumental effects from IRAC using machine learning. This method removes systematics from exoplanet transit data no matter if the noise source is from an instrument or a star. Speaking of transits, Kepler was one of the shining stars of this meeting. The original mission observed 150,000 stars continually for months during its first run, as it was designed to be a statistical mission. But can its findings be considered fully complete in planet radii and orbital periods? Joseph Catanzarite (SETI Institute) aims to answer this question by performing numerous simulations (“injections”) in order to validate our estimations of planet occurrence rates from transit data.

During Kepler’s primary mission, it was relatively easy to identify eclipsing binaries — which are a common type of false positive in exoplanet detection — owing to the spacecraft’s stability. Fergal Mullally (Kepler Science Office) points out that this is not true for K2, due to its continual drift from the pressure of sunlight. They are currently developing dave, a Python program that aims to find and vet planets from K2 data.


Another tool being developed for K2 data analysis is Robovetter, which was introduced by Susan Thompson (SETI Institute, NASA Ames). This new software will allow astronomers to fully and uniformly automate the creation of the final KOI (Kepler Object of Interest) catalog. And what about the science being done by K2? Jessie Christiansen (NASA Exoplanet Science Institute, Caltech) explains that it will not look for Earth-like exoplanets, but will instead be more flexible in the types of targets and their positions on the sky, allowing us to build a census of planets in the galactic plane.

Black Holes and Supernovae (by Ashley Villar)

There are still many open questions about supernovae and their progeny, black holes. Some of these questions will hopefully be answered by LIGO, though many will be solved using the electromagnetic radiation we detect from these sources.

Anthony Piro began the session by explaining his new models which trace the diffusive cooling of an initial supernova shock. His team has created an open source code, the SuperNova Explosion Code or SNEC, to allow others to explore a variety of explosion properties. Janie De La Rosa then spoke about her work on observing Type IIn supernovae (those with narrow emission lines in their spectra) at ultraviolet and optical wavelengths. These wavelengths are sensitive to progenitor models and the geometry of the surrounding material.

Cas A

Composite image of the supernova remnant Cassiopeia A, using data from the Chandra X-ray telescope, NASA’s Spitzer Space Telescope, and ground-based facilities. [NASA/CXC/SAO]

Following the exploration of progenitor geometry, Douglas C. Leonard spoke about his work in hunting for polarization in type IIP supernovae (those with long, plateaued light curves). A high degree of polarization implies asymmetry in the explosion itself, and he has been able to find such asymmetry in a number of type IIP supernovae. He pointed out that “bubble”-like structure (like what we see in the beautiful supernova remnant Cassiopeia A) might explain the polarization as well.

Switching gears, Karri Kolijonen spoke about an interesting X-ray binary (a binary consistent of a compact object and star that emits strongly in X-rays) known as GS 1354-64. This pair has an extremely short orbital period of just two and a half days! He explained how an instability in the black hole’s accretion disk might explain a recent outburst in the system.
Thomas Pannuti explained the basic morphologies of supernova remnants: shell, composite, and mixed. He has taken extensive, multiwavelength images of a mixed remnant known as W28 from radio through X-ray wavelengths. He notes that the radio masers in the remnant are offset from the X-ray light, although the significance of this is still an open question.
Finally, Maria Dainotti wrapped up the session with a discussion of long duration GRBs as standard candles. She finds that, like type Ia supernovae, the light curves of GRBs can be renormalized and standardized with a small scatter in their diversity. Because GRBs are so much brighter than type Ia supernova, these objects could be used as standard candles at much larger distances, and therefore probe the expansion of the universe at much earlier times.
Invisible black holes warp the space time around them in the center of a busy, dense cluster of stars.

Editor’s Note: This week we’re at the 228th AAS Meeting in San Diego, CA. Along with a team of authors from astrobites.com, I will be writing updates on selected events at the meeting and posting twice each day. Follow along here or at astrobites.com, or catch our live-tweeted updates from the @astrobites Twitter account. The usual posting schedule for AAS Nova will resume next week.

Wikipedia “Year of Science” Edit‐a‐thon (by Meredith Rawls)

What’s your first go-to source for an unfamiliar topic on the internet? If you said Wikipedia, you’re not alone. For many people, Wikipedia is the primary source of information about astronomy and science. However, many Wikipedia articles about science topics are incomplete or missing, and women are underrepresented among scientists with biographies.

To address this, the AAS Astronomy Education Board teamed up with the Wiki Education Foundation to host an edit-a-thon as part of the Wikipedia Year of Science. More than forty attendees spent the better part of three hours working through tutorials, creating new articles, and editing existing ones. The session was generously sponsored by the Simons Foundation.

The Year of Science initiative seeks to bring Wikipedia editing skills to the classroom and help new editors find sustainable ways to contribute to Wikipedia in the long term. Anybody can create a free account and start editing!

As a first-time Wikipedia contributor, I took the time to go through nearly all the tutorial exercises and familiarize myself with the process of editing a page. I decided to flesh out one section in an existing page about asteroseismology. Others created biography pages from scratch or selected various astronomical topics to write about. To me, the editing process felt like a cross between writing a blog post and a journal article, in a hack day type environment. Working through the tutorial and some examples renewed my empathy for learners who are tackling a new skill set for the first time. A full summary of our contributions is available. Altogether, we contributed nearly 13,000 words to 44 articles.

The Limits of Scientific Cosmology: The Way Forward (by Gourav Khullar)

After the town-hall with an open mic that raised exceptional questions in the morning, some of the pioneers of the field of scientific cosmology were here with their concluding remarks about the future of the field. John Carlstrom laid down the pipeline for future surveys that not only provide us with interesting constraints on current physics, but give us the opportunity to test new physics. He discussed the CMB, galaxy cluster growth, the Hubble constant and Baryonic Acoustic oscillations as parameters that would define our model of the universe cohesively in the future. The importance of facilities like LSST, SKA, DESI, CMB-S4 were discussed, and Carlstrom emphasized that over the next two decades these fantastic machines will decide the fate of scientific cosmology. Leonard Susskind followed this up with a theoretical framework of how the ideas of inflation and vacuum energy could lead to our understanding of whether String Theory could be the correct theory of the universe.

He touched upon multiverses with his analogy of ‘a submarine floating in a sea with just the right amount of buoyancy balancing gravity’ – a multiverse can have universes with different parameterized cosmological constants! Moreover, in Susskind’s opinion, the only true limit that inhibits our understanding of the features of our universe beyond the cosmic event horizon was the event horizon of an event or phenomena. Jim Peebles concluding this mesmerizing series of talks with his opinions on how physics ought to be direct and assertive with its theories, and should take pride in its explanatory power (or should it?).

 His comparison of local vs. high-redshift cosmology in terms of scales of problems was outstanding, and he encouraged the audience and the community to keep an open mind. After all, in Sean Carroll’s words, we do live in a “preposterous universe”, and the time is almost right to explain it all.

Press Conference: Black Holes and Gamma-Ray Bursts (by Susanna Kohler)

The final press conference of the meeting covered three topics from the categories of black holes and gamma-ray bursts.

Fred Rasio (CIERA/Northwestern University) opened the conference with a discussion of how the systems that LIGO detected might have formed. There are two primary models for how these black-hole binaries are created. In the first, they start out as binary systems of two massive stars. If the binary survives the process of both stars collapsing into black holes, then a binary black hole system results.
Rasio focused on the second theory, in which that black holes are formed in dense stellar clusters. These black holes then sink (via dynamical friction) to the centers of the clusters like dust particles settling on the floor of a room, where they form binaries in a “black hole mosh pit” — eventually getting kicked out of the cluster by dynamical interactions. You can read more about their research in the press release here.
black hole

The effects of a spinning black hole on the spacetime around it. [J.P. Eekels & J.M. Overduin]

Next up was Richard Henry (Johns Hopkins University), who spoke about the internal structure of spinning black holes (known as Kerr black holes). Because no light can escape from black hole interiors, we can’t learn what’s in them via observation. Instead, we rely on mathematical descriptions of what their interiors look like. Henry and collaborators have developed a new coordinate-invariant depiction of the structure of black holes that reframes how we think about visualize their interiors. More information can be found in their paper here.

The final press conference presentation was given by Maria Dainotti (Stanford University) on the subject of using gamma-ray bursts (GRBs) as standard candles. Standard candles are astrophysical sources that have known luminosities. We can use the light we observe from standard candles to estimate their distance, making them useful tools for testing cosmological models.
Type Ia supernovae (which always have roughly the same source brightness) are a typical example of a standard candle, and led to the discovery of dark energy in the 1990s. But if GRBs could be used in a similar way, they would be a much more powerful tool: they’re visible out to significantly further distances because they’re so bright. Dainotti and collaborators are analyzing a subset of GRBs from Swift observations that they term “gold GRBs”. By examining the correlations between parameters of these gold GRBs, Dainotti attempts to understand whether they can be used as standard candles.

Plenary Session: From the First Stars and Galaxies to the Epoch of Reionization: 20 Years of Computational Progress (by Gourav Khullar)

Mike Norman’s (University of California – San Diego) plenary talk concluded the AAS Plenary sessions with a treatise on the current generation of simulations that aim to characterize the first stars and galaxies that formed in the Universe.

Mike has been working in the field for a long time, and his collaborators’ work on the Enzo simulations is very well known. This talk was centered around some of the latest Enzo results, with a special emphasis on tracking down the Epoch of Reionization with a new series of runs called the Renaissance simulations. These runs focused on the most primeval galaxies ever formed in a cosmological box. Mike’s team uses Blue Waters, USA’s fastest supercomputer, situated in NCSA at Urbana-Champaign, Illinois (which also manages the large datasets coming out of the Dark Energy Survey!). The talk described the initial dark matter and gas dynamics along with a dark energy-supported metric evolution using simulations of a cosmic box that was the initial universe. The linear fluctuations of this ‘initial universe’ formed the first stars (called Population III stars in the astrophysics community) from hydrogen and helium generated in the Big Bang. Mike and his team established a catalogue of these first stars, and parameterized these into a function that modeled how these stars became the first galaxies, and eventually into the larger galaxies from the merger of smaller galaxy halos.

The statistics of these first galaxies (from the above mentioned Renaissance simulations) show that the first galaxies formed around a redshift of z = 20, roughly around the same time as the first stars, and way before the actual epoch of reionization (at z ~ 7, the concept is described here). The simulation results extended this evolution to the epoch of reionization and put interesting constraints on observations of this epoch, when we can actually see the ionized gas from this epoch in our observations. Investigations are ongoing, and Mike Norman’s team is positive that the Enzo simulations are here to stay for a long time, challenging and collaborating with observations along the way.

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