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Greetings from the 53rd meeting of the AAS Division for Planetary Sciences, happening virtually anywhere! This week, AAS Nova editor Susanna Kohler and I, along with a team of writers from the Astrobites collaboration — Briley Lewis, Macy Huston, Sabina Sagynbayeva, Sasha Warren, and Ali Crisp — will be bringing you updates on some of the exciting science from the virtual conference. Check back here or on astrobites.org on Wednesday and Friday for summaries of plenary sessions, press conferences, and more!

In honor of the DPS meeting, we’re declaring this week Planetary Sciences Week here at AAS Nova; in addition to summaries of research presented at the DPS meeting, be on the lookout for more planetary science content throughout the week. The usual posting schedule for AAS Nova will resume on Monday, October 11.

In the meantime, here are a few upcoming events that might interest you. We hope to see you there!

  • DPS 53 Daily Press Conferences
    Monday (10/4) – Thursday (10/7), 11:00 am – 12:00 pm ET
  • Webinar: The Planetary Science Journal’s Publishing Process
    Tuesday (10/5), 11:30 am – 12:00 pm ET
  • Webinar: Sharing Planetary Science: Engaging Audiences Virtually
    Tuesday (10/5), 3:30 – 4:00 pm ET
  • Webinar: Perspective: How the PDS Fits Into the Larger Planetary Data Ecosystem
    Wednesday (10/6), 12:00 – 1:00 pm ET
  • Webinar: Volunteer Opportunities with Webb in 2022
    Thursday (10/7), 11:30 am – 12:00 pm ET
  • Attendee Event: The Art of Planetary Science, happening all week!

Don’t forget to check out the informal Science Chats throughout the week, stop by the virtual exhibit hall, and say hello in Gathertown!

 

Stellar Nurseries in the Palm of Your Hand

Editor’s note: AAS Nova is on vacation until 22 September. Normal posting will resume at that time; in the meantime, we’ll be taking this opportunity to look at a few interesting AAS journal articles that have recently been in the news or drawn attention.

When art and science meet, beautiful things can happen. For the first time, scientists have used 3D printing to create tangible models of molecular clouds. Nia Imara (University of California, Santa Cruz) and collaborators first performed a series of nine simulations in order to test how gravity, magnetism, and turbulence affect the formation of gas clumps and filaments in star-forming regions. Using a combination of opaque and transparent materials, they then printed multiple 8-centimeter-wide spheres and hemispheres to showcase the results of their simulations.

Their 3D-printed models demonstrate the effects of changing various physical parameters and highlight structures that can be hard to identify in 2D representations of 3D simulations. For example, cranking up the magnetic field strength suspends gas filaments along the magnetic field lines, while suppressing the magnetic field allows the gas to collapse, leaving behind voids. In addition to the scientific benefits of these models, the authors hope that their hand-held nature will make them a useful tool for outreach and education.

Original article: “Touching the Stars: Using High-resolution 3D Printing to Visualize Stellar Nurseries,” N. Imara et al 2021 ApJL 918 L3. doi:10.3847/2041-8213/ac194e

University of California Santa Cruz press release: Astronomers Create the First 3D-Printed Stellar Nurseries

Planets, Planets Everywhere (Not Just Where You'd Think)

Editor’s note: AAS Nova is on vacation until 22 September. Normal posting will resume at that time; in the meantime, we’ll be taking this opportunity to look at a few interesting AAS journal articles that have recently been in the news or drawn attention.

microlensing diagram

A diagram of how planets are detected via gravitational microlensing. The detectable planet is in orbit around the foreground lens star. [NASA]

Most of the exoplanets we’ve discovered are located within about 3,300 light-years of Earth, leaving the distribution of planets across the rest of the Milky Way a mystery. To tackle this question, a team of astronomers led by Naoki Koshimoto (NASA Goddard Space Flight Center) analyzed observations of 28 planets discovered with gravitational microlensing — a technique that can detect planets at far greater distances than the transit or radial-velocity techniques. They compared the characteristics of the observed microlensing events against what would be expected if planets tend to be clustered near the galactic center, sequestered on the edges of the galactic disk, or distributed more evenly throughout the Milky Way.

Based on the observations, the team found that planet frequency is only weakly dependent upon distance from the galactic center. This result suggests that planets are likely to be found throughout the galaxy, though the results don’t fully rule out the possibility that planets could be rare near the galactic center — especially if the masses of the lensing objects tend to be small. As the number of planets discovered with gravitational microlensing grows, astronomers should gain a better understanding of how planets are distributed throughout the Milky Way.

Original article: “No Large Dependence of Planet Frequency on Galactocentric Distance,” N. Koshimoto et al 2021 ApJL 918 L8. doi:10.3847/2041-8213/ac17ec

Osaka University press release: Cold Planets Exist Throughout Our Galaxy, Even in the Galactic Bulge

Heavy Metals Hint at an Unusually Dense White Dwarf

Editor’s note: AAS Nova is on vacation until 22 September. Normal posting will resume at that time; in the meantime, we’ll be taking this opportunity to look at a few interesting AAS journal articles that have recently been in the news or drawn attention.

A team of astronomers led by Yuken Ohshiro (University of Tokyo) used X-ray observations from the space-based XMM-Newton observatory to detect the presence of heavy metals in supernova remnant 3C 397. They discovered a region that is rich in titanium and chromium in addition to the more commonly found manganese, iron, and nickel. The ratios of the abundances of these elements suggest that they formed in a white dwarf with a central density of 5 x 109 g cm-3, which is more than twice as dense as expected for a white dwarf at the Chandrasekhar mass limit — the maximum mass white dwarfs are thought to be able to attain.

This finding suggests that the white dwarfs that give rise to Type Ia supernovae are not identical, instead having a range of central densities. Because Type Ia supernovae are considered standard candles — cosmic beacons of equal luminosity that allow us to gauge distances to far-off galaxies — it’s crucial to understand whether their white-dwarf progenitors are as uniform as expected. Extending this measurement technique to other supernova remnants should clarify our understanding of these objects and ensure that Type Ia supernovae can continue to be used as precise standard candles in the future.

Original article: “Discovery of a Highly Neutronized Ejecta Clump in the Type Ia Supernova Remnant 3C 397,” Yuken Ohshiro et al 2021 ApJL 913 L34. doi:10.3847/2041-8213/abff5b

JAXA Institute of Space and Astronautical Science press release: A rogue in the “Cosmic Standard Candle”? The relic of the densest white dwarf has been detected in the remnant of its supernova

Illustration of a compact star with beams of light emitting from its poles.

Editor’s note: AAS Nova is on vacation until 22 September. Normal posting will resume at that time; in the meantime, we’ll be taking this opportunity to look at a few interesting AAS journal articles that have recently been in the news or drawn attention.

What’s inside the dense interior of a neutron star, the remnant left behind at the end of a massive star’s evolution? Scientists have now searched for the answer to this question using new observations of an extreme neutron star from NASA’s Neutron star Interior Composition Explorer (NICER).

schematic illustrating the different layers of a neutron star, including an unknown inner core

Scientists think neutron stars are layered. As shown in this illustration, the state of matter in their inner cores remains mysterious. [NASA’s Goddard Space Flight Center/Conceptual Image Lab]

Neutron star J0740+6620 is the heaviest neutron star that’s been precisely measured — and correspondingly precise measurements of its radius could provide the key to finally figuring out what its interior structure looks like. In a set of recent studies, one led by Cole Miller (University of Maryland) and the other by Thomas Riley (University of Amsterdam), two teams of scientists used NICER’s X-ray observations of J0740 to obtain accurate measures of the star’s radius using two different approaches. They found that J0740’s 2.1 solar masses are packed into a sphere just 25–27 km across.

These new results, combined with previous measurements of other neutron stars, are helping us to understand whether neutron stars are made up primarily of neutrons in their interior, or whether the pressure is so great that those neutrons have disintegrated into a soup of particles called quarks. A study led by Geert Raaijmakers (University of Amsterdam) uses these observations to place significant constraints on the so-called neutron star equation of state, which describes neutron star interiors.

To learn even more about this work, be sure to check out the summary video from NASA’s Goddard Space Flight Center below.

Original articles:
“The Radius of PSR J0740+6620 from NICER and XMM-Newton Data,” M. C. Miller et al 2021 ApJL 918 L28. doi:10.3847/2041-8213/ac089b
“A NICER View of the Massive Pulsar PSR J0740+6620 Informed by Radio Timing and XMM-Newton Spectroscopy,” Thomas E. Riley et al 2021 ApJL 918 L27. doi:10.3847/2041-8213/ac0a81
“Constraints on the Dense Matter Equation of State and Neutron Star Properties from NICER’s Mass–Radius Estimate of PSR J0740+6620 and Multimessenger Observations,” G. Raaijmakers et al 2021 ApJL 918 L29. doi:10.3847/2041-8213/ac089a

Press releases:
University of Maryland: NASA’s NICER Probes the ‘Squeezability’ of Neutron Stars
University of Amsterdam: Astronomers Measure Heaviest Known Neutron Star With Telescope on ISS

Photograph taken at night showing three radio dishes in part of an array.

Editor’s note: AAS Nova is on vacation until 22 September. Normal posting will resume at that time; in the meantime, we’ll be taking this opportunity to look at a few interesting AAS journal articles that have recently been in the news or drawn attention.

A team of scientists has used the Giant Metrewave Radio Telescope (GMRT) to measure the amount of atomic hydrogen gas — the main fuel for star formation — in galaxies at redshifts of z = 1.18–1.39, or roughly 9 billion years ago. Led by Aditya Chowdhury (National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, India), the team obtained sensitive observations of these distant galaxies with the upgraded GMRT, an array of thirty 45-meter radio dishes located in India.

Star formation activity in our universe is known to have peaked around 8–10 billion years ago before declining steadily thereafter. By probing atomic hydrogen gas 9 billion years ago — the earliest epoch for which we’ve made these measurements yet — Chowdhury and collaborators showed that galaxies at this time contained vast reservoirs of fuel. This outcome supports the idea that our universe’s declining star formation is tied to depletion of these fuel reserves.

Original article: “Giant Metrewave Radio Telescope Detection of Hi 21 cm Emission from Star-forming Galaxies at z ≈ 1.3,” Aditya Chowdhury et al 2021 ApJL 913 L24. doi:10.3847/2041-8213/abfcc7

National Centre for Radio Astrophysics, Tata Institute of Fundamental Research press release:
GMRT Measures the Atomic Hydrogen Gas Mass in Galaxies 9 Billion Years Ago

Five images show different gas velocity components of an elliptical protoplanetary disk surrounding a young star.

Editor’s note: AAS Nova is on vacation until 22 September. Normal posting will resume at that time; in the meantime, we’ll be taking this opportunity to look at a few interesting AAS journal articles that have recently been in the news or drawn attention.

Scientists have made a new, unusually accurate measurement of the mass of the protoplanetary disk orbiting around the young star Elias 2–27. The masses of protoplanetary disks — the disks of gas and dust that surround young stars, in which planets form — are highly uncertain. This inability to precisely measure how much matter is available to form baby planets limits our ability to understand the planet formation processes, so better means of measuring disk masses are needed.

In a new study led by Benedetta Veronesi (University of Milan, Italy), a team of scientists has now leveraged multiwavelength observations from the Atacama Large Millimeter/submillimeter Array (ALMA) to track the rotation curve of the disk around Elias 2–27, disentangling the gravitational influence of the central star from the self-gravity of the disk. This allowed the team to make the first dynamical measurement of this protoplanetary disk’s mass — which provides a much more accurate measurement than previous methods and lays the groundwork for extending this technique to other systems.

Original article: “A Dynamical Measurement of the Disk Mass in Elias 2–27,” Benedetta Veronesi et al 2021 ApJL 914 L27. doi:10.3847/2041-8213/abfe6a

National Radio Astronomy Observatory (NRAO) press release:
Study of Young Chaotic Star System Reveals Planet Formation Secrets

Gif animation shows different views of the disk around Elias 2-27 at different wavelengths

This animation shows the different molecular tracers used to better understand the gases present in the disk surrounding Elias 2-27. Seen are the 0.87mm dust continuum data (blue), C18O emission (yellow), and 13CO emission (red), with each layer shown individually and in composite. [ALMA (ESO/NAOJ/NRAO)/T. Paneque-Carreño (Universidad de Chile), B. Saxton (NRAO)]

Illustration of an enormous loop of plasma erupting from the surface of a dim, red star.

Editor’s note: AAS Nova is on vacation until 22 September. Normal posting will resume at that time; in the meantime, we’ll be taking this opportunity to look at a few interesting AAS journal articles that have recently been in the news or drawn attention.

Astronomers have observed the largest stellar flare ever recorded from Proxima Centauri, our nearest stellar neighbor. Detected in May 2019, the flare was recently reported in a publication led by scientist Meredith MacGregor (University of Colorado Boulder). During the flare, MacGregor and collaborators observed Proxima Centauri to brighten by a factor of more than 1,000 in millimeter emission, and by a factor of more than 14,000 in ultraviolet emission.

Studying the combination of these flare signals helps us to better understand what triggers these powerful flashes and how they evolve. This, in turn, provides valuable information about the radiation environment surrounding rocky, inner planets — planets like Proxima Centauri b, which lies in Proxima Centauri’s habitable zone but may be at risk of being cooked by bright and energetic flares from its host.

Original article: “Discovery of an Extremely Short Duration Flare from Proxima Centauri Using Millimeter through Far-ultraviolet Observations,” Meredith A. MacGregor et al 2021 ApJL 911 L25. doi:10.3847/2041-8213/abf14c
University of Colorado Boulder press release: Humongous flare from sun’s nearest neighbor breaks records

Photograph of a female speaker at a podium next to a row of seated panelists behind a banner that reads "American Astronomical Society"

We’re delighted to (re-)introduce Kerry Hensley, a planetary scientist who has recently joined the AAS staff as our Communications Specialist. You can expect to see Kerry in person at future AAS meetings in her capacity as the AAS Deputy Press Officer. In addition, Kerry will serve as co-editor of AAS Nova — so you’ll be seeing her byline on research highlights in the near future!

Photograph of Kerry Hensley, the new AAS Communications Specialist

AAS Communications Specialist Kerry Hensley

Kerry is not new to the AAS’s ranks: You may remember her from her term as the inaugural AAS Media Fellow (a quarter-time position for graduate students in the astronomical sciences who wish to cultivate their science communication skills, a position currently held by Tarini Konchady). Over the span of her 1.5-year fellowship term, Kerry helped to plan and run press conferences at AAS meetings, assisted in operating the AAS press release distribution service, and wrote and published articles here on AAS Nova.

Since concluding her fellowship term at the AAS, Kerry was selected as an American Association for the Advancement of Science (AAAS) Mass Media Science and Engineering Fellow and served as a science journalist for Voice of America, writing articles and scripting, voicing, and producing radio and video stories. Her past science communication pursuits include freelance writing (with bylines in publications like Sky & Telescope magazine), presenting planetarium shows, and writing and editing for Astrobites.

Kerry earned her BA in astrophysics and Chinese at Williams College and will shortly defend her PhD dissertation work in planetary atmospheres at Boston University. We’re excited to welcome her on board!

Orange banner containing the open access logo, a stylized open lock.

We usually don’t put exclamation points in titles around here, but we’re really excited about this one. As of 1 January 2022, all AAS journals will officially be open access (OA) — which means that anyone can read, download, and share the content in them with no subscription charge. We think this is a huge and important step in our efforts to increase equity and the sharing of knowledge in astronomy, and we hope that you agree!

For the full details about this change, you can read our press release and our detailed FAQ. And if you’re new to the world of academic publishing, check out CfA/AAS Innovation Scientist Peter Williams’s excellent — and honest — summary of the scene and how AAS’s move to OA fits in.

Here, we’ll just briefly outline this transition and a few of its implications so you can see how this might impact you as a member of the astronomy community.

Wait, What’s Happening?

After 1 January 2022, all AAS journals will transition to an open access model. This means no more subscriptions, paywalls, or access control on any past, present, or future AAS journals content after 31 December 2021.

images of the covers of the six aas journals with open access logos superposed on each

All AAS journals will be open access on 1 January 2022.

The transition will apply to the Astronomical Journal (AJ), the Astrophysical Journal (ApJ), Astrophysical Journal Letters (ApJL), and the Astrophysical Journal Supplement Series (ApJS); the Planetary Science Journal (PSJ) and Research Notes of the AAS (RNAAS) are both already open access.

A Little Background on the Business

Until recently, most scholarly journals have been 100% supported by institutional subscriptions: institutes pay so their researchers can read articles in the journals. This model has the benefit of allowing authors to publish without charge — but it has the significant downside of limiting who is able to see that research.

AAS has relied for decades on a hybrid model, in which ~1/3 of journal revenue comes from institutional subscriptions and ~2/3 from article publication charges. This helps distribute the financial burden better and reduces the time that articles are paywalled (only 12 months after publication).

The move to fully open access — in which article publication charges will represent 100% of the support for the journals — takes this a step further. Under an open access model, no amount of the financial burden falls to the reader, and anyone is able to see the research in AAS journals immediately upon publication.

Hang On, What About the Authors?

At this point, you may be wondering: We’re removing the barrier to accessing the research in our journals — but doesn’t this just introduce a new barrier to publishing it?

We want to avoid that, which is why we’ve introduced a significantly expanded waiver budget into our new pricing model. Authors who don’t have the funds to publish with us can apply for a waiver of article publication charges, and the Editor in Chief can authorize waivers based on need.

That said, authors who do have the funds to publish with us are expected to pull their weight! We did our best to get the costs as low as possible while still covering the loss of subscription revenue and the increased waiver budget. We hope that the community will see this transition to OA as a positive move toward increased inclusivity, and that those who can afford it will continue to step up — as they’ve already done for decades — to pay their share and help ensure that anyone who wants to submit to AAS journals can, regardless of financial situation.

What This Transition Means for You

If you’re an amateur astronomer or enthusiast, this change should give you the freedom to more easily pursue your interests. Ever been annoyed when you’ve followed the link to a really awesome-sounding article and gotten stuck at a paywall? That won’t happen with us anymore. After 1 January 2022, be ready to dive into any exciting astronomy that catches your eye.

If you’re a researcher who publishes with AAS journals, know that after 1 January 2022, your article will be immediately available for anyone in the world to read. Page charges will likely be a little higher, but that money’s going toward making science an inclusive and open enterprise. And our data shows that, statistically, your open-access work will be even more likely to be cited and downloaded, which is a nice perk.

And if you’re a researcher who doesn’t publish with AAS journals, well — what better time to start?

Ultimately, the upcoming transition to our new model won’t change the high-quality research published in the AAS journals. It just removes the barriers to who can create, discover, share, and build on that research — in short, who can participate in astronomy. And that’s an outcome we hope everyone can be excited about.

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