Dear friends,

Fall quarter is my favorite time of the year at the University. We get to welcome our new graduate students, undergrads come back to the campus, and the work of teaching, research, and engaging the community begins in earnest. This is the time when new ideas begin to take shape, projects start, and everything seems possible.

I’m feeling a sense of almost unbounded possibility especially this year at DiRAC, as we are working through the first days of the Rubin Observatory’s operations. This summer we celebrated major milestones, including the amazing “First Look” event we hosted at Kane Hall in June. As the “commissioning” phase comes to a close, and the Observatory prepares for full operations near the end of the year, our team is preparing for a flood of science and discovery.

We were able to practice a bit of this Rubin-driven discovery over the summer, thanks to the first “Data Preview” that the Observatory published. With truly a tiny sliver of LSST/Rubin data in hand, students and faculty from our entire department came together for a week to explore and collaborate. These kinds of “sprints” are a fun way for everyone to quickly learn new skills, and for our team to push out early science. I promised fabulous prizes for the first publications to come out of this Data Preview sprint, and I’m especially proud of the graduate students David Wang and Tobin Wainer who took home the trophies!

In the Newsletter you’ll see profiles from many of our research programs. Our Solar System group is now firmly established worldwide as one of the premier groups working on asteroids, comets, and the enigmatic “interstellar objects”, and I’m in awe at how quickly they rallied the Rubin community to study the incredible new object, 3I/ATLAS. I am baffled and fascinated by the discovery of ultra-fast rotating asteroids, which Sarah Greenstreet’s team has recently announced. Our newest postdoctoral fellow, Nick Tusay, is broadening our Time Domain group’s expertise into data from JWST and the new field of disintegrating exoplanets. The science at DiRAC continues to evolve and explore some of the most exciting topics across astrophysics!

I’m also thrilled that we are beginning the search for our next cohort of DiRAC postdoctoral researchers, who will be pushing the frontiers here at UW of science as Rubin makes its first full data release. Thanks to the support of our community, and especially the incredible partnerships with the Simonyi and Frink families, and the B612 Institute, we are able to continue supporting innovative science, as well as continue building a welcoming and energetic environment for discovery. I am so grateful for the many opportunities I’ve had at DiRAC, and being able to continue this Fellowship program for the next generation of astronomers is a dream come true.

Here’s to a Fall full of new beginnings, community, and exciting discoveries.

Keep looking up!

Jim Davenport
DiRAC Director

We are pleased to welcome Nick Tusay, who joined the team this September as a DiRAC Postdoctoral Fellow. Nick focuses on the search for extraterrestrial intelligence (SETI) and habitable worlds research. His SETI work has been executing and analyzing the results of novel search strategies to look for radio technosignatures using observatories like the Green Bank Telescope and the Allen Telescope Array. His work on exoplanets has largely been focused on directly measuring the chemical components of disintegrating rocky bodies around main sequence stars to test our understanding of planet composition using both state-of-the-art ground-based optical observatories as well as space-based observatories like JWST. 

Nick is excited to be co-PI on a JWST Cycle 4 Program to observe a recently discovered disintegrating exoplanet, BD+05 4868 Ab, executing this October. Using transmission spectroscopy in mid-infrared, his team will measure the spectrum of the dusty effluents coming off the planet and try to match that with features of known materials. It’s an exciting and rare opportunity to examine the interior composition of a rocky exoplanet around a main sequence star. 

The NSF-DOE Vera C. Rubin Observatory’s First Look media event that took place on June 23, 2025 in which the first LSST Camera commissioning images were released, included the announcement of its first asteroid discoveries – 2,103 discoveries in all. The roughly 340,000 individual detections in which the 2,103 discoveries were made span 9 nights between April 21 and May 5, 2025. With a faint magnitude range (~23-25 mag) and dense temporal sampling under an irregular, commissioning‑driven cadence, the Rubin First Look observations provide an ideal testbed for determining asteroid rotation periods, including the detection of rapid rotation. In a paper, currently in press in The Astrophysical Journal Letters, NSF NOIRLab Assistant Astronomer and UW Astronomy Affiliate Assistant Professor Sarah Greenstreet, UW Astronomy graduate student Chester Li, UW Astronomy postdoctoral scholar Dmitrii Vavilov and their colleagues present light curves, rotation periods, and colors for the first asteroid discoveries made with the NSF-DOE Vera C. Rubin Observatory. 

The paper includes modeled light curves and derived rotation periods and colors for the 2,103 objects, finding 75 asteroids with reliable, robust rotation periods spanning < 2 minutes to > 21 hours; each of the 75 asteroids in the data set reside in the Solar System’s main asteroid belt between the orbits of Mars and Jupiter. Notably, they find 18 super-fast rotators with periods shorter than the 2.2-hr spin barrier; the spin barrier is the maximum rotation rate an object can sustain before the centrifugal force overcomes self-gravity, potentially leading to structural fragmentation of the asteroid or the formation of a binary asteroid. Surprisingly, they additionally find that Rubin-discovered main-belt asteroid (MBA) 2025 MN45 is now the fastest rotating known asteroid with a diameter larger than 0.5 km (longer than the length of 5 football fields), rotating once every 1.9 min! Along with Rubin-discovered near-Earth object (NEO) 2025 MJ71 (3.7 min) and MBAs 2025 MK41 (3.8 min), 2025 MV71 (13 min), and 2025 MG56 (16 min), these five ultra-fast rotators now join a couple of previously-known near-Earth asteroids as the fastest spinning sub-km asteroids known.

As this study demonstrates, even in early commissioning, Rubin is successfully probing the previously sparsely sampled population of large-sized asteroids that reside at greater distances than other astronomical surveys have been able to observe spinning at these very fast rotation speeds. Although this data set consists of observations taken at a different cadence, subject to the requirements of Rubin’s commissioning period, than will be followed during Rubin’s Legacy Survey of Space and Time (LSST), expected to start later this year, with millions of asteroid discoveries expected from the survey in the coming years, the findings of this study are just the beginning of the exciting science the Rubin Observatory will unlock and the astronomers at UW Astronomy’s DiRAC Institute are poised to lead.

About Sarah Greenstreet

Sarah Greenstreet is a tenure-track assistant astronomer at the NSF National Optical-Infrared Astronomy Research Laboratory (NOIRLab) and an affiliate assistant professor in the University of Washington’s Department of Astronomy. She is also a member of the Rubin Observatory Community Science Team and has served as the Lead for the Rubin Observatory Solar System Science Collaboration’s Near-Earth Objects and Interstellar Objects Working Group for the past seven years. Prof. Greenstreet’s research program broadly focuses on orbital dynamics, characterization, and impacts of small bodies across the Solar System, with a particular focus on the rarest and most unusual asteroids. To learn more about her research, please visit her website: www.sarahgreenstreet.com.

About Dmitrii Vavilov

Dmitrii Vavilov is a postdoctoral researcher at the University of Washington and a former Marie Skłodowska-Curie Fellow at the Paris Observatory. He studied astronomy at St. Petersburg State University and earned his Ph.D. in celestial mechanics from the Institute of Applied Astronomy of the Russian Academy of Sciences. His research focuses on the dynamics and physical properties of small Solar System bodies (like asteroids and comets) from their dynamical evolution to shape transformations. He developed the Partial Banana Mapping (PBM) method, an efficient approach for modeling orbital uncertainties to predict Earth-impact probabilities, precoveries, and follow-up observations. He is a member of the International Astronomical Union, and asteroid (34583) DmitriiVavilov has been named in his honor.

About Chester Li

Zhuofu (Chester) Li is a Ph.D. student studying Astrophysics, Statistics, and Data Science at the University of Washington. His research integrates data science, astrophysics, and machine learning to explore the mysteries of the Universe. Chester’s recent work includes estimating rotation periods for Jupiter Trojans using Zwicky Transient Facility lightcurves, identifying temporary Jovian co-orbitals through large-scale N-body simulations, and applying simulation-based inference with normalizing flows to constrain dark matter using stellar streams. He is also the founder of the UW Data Science Society, where he builds interdisciplinary collaborations between astronomy, statistics, and computer science.

DiRAC postdoctoral scholar Colin Orion Chandler is leading innovative efforts to explore small bodies in our Solar System using the upcoming Vera C. Rubin Observatory. As Project Scientist for the LSST Interdisciplinary Network for Collaboration and Computing (LINCC) Frameworks, Chandler’s work bridges cutting-edge data systems with frontier planetary science. His Rubin Comet Catchers project—the first Rubin-based Citizen Science program—invites volunteers worldwide to help identify comets and active asteroids hidden in Rubin’s vast imaging data. Since its launch in July 2025, over 1,500 participants have contributed more than 1.5 million classifications, demonstrating the power of community-driven discovery at LSST scale.

Chandler also co-leads the Rubin observations of interstellar comet 3I/ATLAS, representing the first scientific paper derived from Rubin data. The discovery revealed that Rubin had serendipitously imaged the interstellar visitor prior to its detection, offering invaluable insights into the observatory’s capabilities for identifying and characterizing future interstellar objects. With Rubin expected to find 5–50 such visitors over its 10-year survey, this work underscores the observatory’s transformative role in Solar System science and interstellar research.

Together, these efforts highlight how DiRAC researchers are pioneering the intersection of AI-assisted Citizen Science and next-generation astronomical surveys. From training “TailNet” neural networks on volunteer data to coordinating rapid follow-up of unexpected phenomena, Chandler’s team is forging the framework for large-scale, inclusive discovery—ensuring that Rubin’s once-in-a-generation data revolution engages both scientists and the public in revealing our dynamic Solar System.

About Colin Orion Chandler

Colin Orion Chandler (DiRAC and University of Washington) is a Project Scientist for the LSST Interdisciplinary Network for Collaboration and Computing (LINCC) Frameworks project, and serves as co-chair of the LSST Solar System Science Collaboration. Colin earned his Ph.D. in Astronomy and Planetary Science from Northern Arizona University, where he was an NSF Graduate Research Fellow, after he graduated from San Francisco State University with a BS in Physics with a Concentration in Astrophysics. He specializes in solar system science (especially cometary activity), Citizen Science, and working with large-scale archival image data. Colin founded the NASA Partner program “Active Asteroids” (http://activeasteroids.net), a Citizen Science program hosted on Zooniverse. Colin is also an experienced observer, utilizing both ground- and space-based telescopes as part of his work. 

In August 2025, Meredith Rawls, UW/DiRAC Research Scientist and Co-Lead of SatHub at the IAU Centre for the Protection of the Dark and Quiet Sky (CPS), and Brianna Smart, UW/DiRAC Research Scientist, attended an NSF-funded workshop on satellite constellations and Rubin Observatory at UC Davis.

The workshop resulted in a report titled, “Report on LEO satellite impacts on ground-based optical astronomy for the Rubin Observatory LSST,” which was shared on arXiv in September (v1). The report aims to minimize the impact of Starlink-like constellations on LSST science and acknowledges it cannot encompass all satellites or all observatories. Nevertheless, in addition to affirming previous recommendations, including satellite darkening mitigations, low orbital altitudes, and timely data sharing of satellite positions and trajectories, the report introduces new ones, such as coordinated de-orbit strategies, developing metrics that account for the impact of full constellations, and building a comprehensive database of satellite signatures in LSST data down to low surface brightness.

Read the report here.

About Meredith Rawls

Meredith Rawls is a research scientist in the Department of Astronomy and DiRAC at the University of Washington. She writes software to handle terabytes of nightly data from Vera C. Rubin Observatory’s Legacy Survey of Space and Time (LSST), which will ultimately become the highest resolution movie of the night sky ever made. She earned a BS from Harvey Mudd, a MS from San Diego State, and a PhD from New Mexico State. Her background is in stellar astrophysics, but lately she studies the plethora of newly-launched low-Earth-orbit satellites in the hopes observers worldwide don’t lose the night sky. She lives with her family in Seattle, enjoys playing viola, and primarily gets around by e-bike.

About Brianna Smart

Brianna Smart is a research scientist in the Department of Astronomy and DiRAC at the University of Washington. She writes software as part of the Alert Productions Data Management group in support of the Vera C. Rubin Observatoriy’s Legacy Survey of Space and Time. She earned her B.S. in Astronomy and Physics at the University of Arizona, and her M.S. and PhD from The University of Wisconsin. Brianna has a varied background in astronomy from exoplanets to stellar dynamics to diffuse ionized gas. She also enjoys any science topic related to the Magellanic Clouds.

Dear friends of DiRAC,

This summer marks an exciting turning point, not just for our Institute, but for astronomy as a whole: after years of anticipation, the construction of the Vera C. Rubin Observatory is finally complete, and the first incredible images have been shared with the world!

It’s amazing to think that this project started almost 20 years ago, and I’m so proud that Seattle and the University of Washington have remained leaders in its design, development, and now discovery with LSST. I hope you will join us in Kane Hall on June 26 as we share these images with our community, and tell a few of the stories of the brilliant and hard-working people who have made this dream a reality.

The summer also marks a turning point for the leadership of DiRAC. I am deeply honored to step in to the role as Director of the DiRAC Institute this year. I joined DiRAC 8 years ago a Postdoctoral Fellow, drawn by the promise of new datasets and a collaborative environment where wild or even silly ideas could find a home. Now as a professor and Director, my goal is to take the scientific momentum built by Andy Connolly and Mario Juric, and support this amazing group of students, developers, and researchers into an era of unprecedented discovery. These are uncertain times for science. The broader funding and academic landscape is rocky, and it can feel harder than ever to plan for the long term. But if these past 8 years have taught me anything, it’s that imagination, persistence, and compassion are powerful force multipliers. Whether we’re tracking near-Earth asteroids, developing novel algorithms, or chasing the weird and wonderful outliers in our data, we thrive when we let curiosity lead the way.

I am so grateful that our community has continued to support us, funding a 4th year of our Summer Research Prize program, and new generations of Postdoctoral Fellows at DiRAC. So here’s to the coming decade of discoveries with Rubin/LSST. Here’s to students asking bold questions from our data. And here’s to finding joy – even a little absurdity – in the vast puzzle of the cosmos.

Thank you for being part of this journey with us, and keep looking up.

Jim Davenport
DiRAC Director

Dear DiRAC supporters,

Welcome to 2025 and to a new installment of our newsletter.

And what a year it’s been so far! In October of last year, after almost two decades of research, development, and construction, we welcomed the first engineering light with the test camera at the Rubin Observatory. The first image, unveiled at the January American Astronomical Society’s meeting by Rubin Construction director and UW DiRAC Faculty Prof. Zeljko Ivezic, shows the potential of the observatory and foreshadows the next decade of discovery. We’re now working towards the first light with Rubin’s main camera, and marching towards the end of this year when Rubin will embark on its 10 year mission to map the Universe in both space and time.

Read more about Rubin, events at the Institute, profiles of our excellent DiRAC team members, as well as how our Prof. Nora Shipp won a Scialog Collaborative Innovation Award, in the main part of this newsletter.

But before I let you go, there’s one more thing… Following nearly five years of being at the helm of DiRAC, it’s a privilege to welcome Prof. Jim Davenport as the new incoming Director! Jim is Research Associate Professor in the department of Astronomy, and has been DiRAC’s Associate Director for nearly all of my tenure. His impact on the institute cannot be underestimated: from revitalizing our time-domain program to leading numerous outreach and education initiatives — including the highly successful DiRAC Undergraduate Summer Prize program.

As I prepare to take a Rubin-focused sabbatical next year, I’m incredibly grateful to Jim for agreeing to step up and take on this responsibility. As we finally enter the age of Rubin, there’s no one better I can imagine to lift the Institute to new heights!

Onwards and upwards,

Mario Jurić
DiRAC Director
Professor, Department of Astronomy