Stars and satellites as seen by the Dark Energy Camera

Huge Survey vs. Tiny Space Junk

As construction continues on the Vera Rubin Observatory, the skies above its mountaintop home grow more and more crowded following every rocket launch. Astronomers, conscious of the plans for mega-constellations of new satellites in the next few years, are rightfully worried: will these satellites and the tiny bits of debris that come with every deployment and collision affect the new telescope’s long-awaited, gigantic survey?

Read more about this research featuring DiRAC Fellow Meredith Rawls at AAS Nova!

Citizen Scientists Uncover Hidden Secrets of the Solar System: “Active Asteroids” Project Reveals Dozens of Rare Celestial Bodies

In a groundbreaking collaboration between scientists and the global community, the “Active Asteroids” Citizen Science project has unveiled a trove of discoveries, shedding light on a poorly understood population of objectspreviously unknown “active minor planets” in our solar system.

Launched on August 31, 2021, through a NASA Partner program hosted on the Zooniverse online platform, the Active Asteroids initiative calls upon volunteers from around the world to assist in the search for active asteroids — a category of rare and elusive small solar system objects characterized by comet-like tails or comae. Studying these objects is crucial for scientists to understand fundamental questions about the formation and evolution of the solar system, including the origins of water here on Earth. Additionally, active asteroids may be valuable for future space exploration because the same ices that are responsible for comet-like tails can also be used for critical resources, such as rocket fuel and breathable air.

2015 VA108:
Volunteers from the NASA Partner “Active Asteroids” Citizen Science project identified a comet tail coming from asteroid 2015 VA108. The prominent tail is pointed roughly towards the 4 o’clock position in this image originally captured with the Dark Energy Camera in October 2015. The object orbits entirely within the main asteroid belt (located between Mars and Jupiter) so the object is classified as an active asteroid and a rare “Main-belt comet” candidate.

Asteroids can also appear active due to impacts from other asteroids or by spinning so fast that material is actually ejected off into space.  Identifying these types of events also helps scientists learn more about how often such events occur and how asteroids behave when experiencing them, which can help inform the design of future asteroid deflection missions like NASA’s recent DART mission to the Didymos asteroid system.

The project, which is ongoing, utilizing publicly available data from the Dark Energy Camera (DECam) on the Victor M. Blanco telescope in Chile, involved the examination of over 430,000 images of known asteroids by 8,300 volunteers. The results, detailed in a recent paper, showcase the power of community engagement in advancing scientific knowledge.

Figure 1: The 16 active object discoveries made by the Active Asteroids program. Each panel shows an object at the center, with a tail or coma (dust cloud) emanating from that object. (Image Credit: Henry Hsieh)

The recent survey conducted by volunteers has led to some groundbreaking findings. A total of 15 new active objects were identified, marking a significant challenge to the conventional wisdom regarding the elusive nature of asteroids. However, the discoveries did not stop there; they extended beyond active asteroids to include a diverse array of celestial phenomena. This includes the identification of one active Centaur, four active quasi-Hilda asteroids, and seven Jupiter-family comets (JFCs). Additionally, the project unearthed unexpected scientific insights, such as the discovery of historical activity on certain objects that was previously unknown. Dynamical analyses conducted during the project also prompted the reclassification of some objects, thereby adding an unforeseen layer of scientific depth to the findings.

Dr. Colin Orion Chandler

Project founder Dr. Colin Orion Chandler, a LINCC Frameworks project scientist at the University of Washington and DiRAC Institute, expressed gratitude for the enthusiastic response from Citizen Scientists. “The collective effort of our volunteers has expanded our understanding of the solar system. The discoveries made by this diverse group of individuals highlight the importance of engaging the public in scientific endeavors.”

Notably, the paper includes nine Citizen Scientists among the co-authors, signifying their critical role in the project’s success. When asked about the motivation behind their project involvement, one Citizen Scientist author, José Campos of Setubal, Portugal, said “I like the Active Asteroid project because it is very dynamic and there is always a good chance to contribute with a discovery.”

The “Active Asteroids” project not only furthers our knowledge of celestial bodies but also demonstrates the potential of Citizen Science in advancing cutting-edge research. The success of this initiative reaffirms the importance of collaborative efforts in exploring the mysteries of the cosmos.

About the Active Asteroids Project:

The Citizen Science program, Active Asteroids, is a collaborative effort between scientists and the global community, hosted on the Zooniverse online platform. Launched in partnership with NASA, the project engages volunteers in the search for rare asteroids with comet tails, uncovering previously unknown celestial phenomena. For more information, visit


Colin Orion Chandler

LINCC Frameworks Project Scientist and Postdoctoral Scholar

DiRAC Institute and the University of Washington

1 206 543 2888

About the DiRAC Institute

The University of Washington’s Institute for Data-Intensive Research in Astrophysics and Cosmology (DiRAC) brings together the diversity of expertise — from astrophysics, data science, to software engineering — needed to build the world’s most advanced datasets and algorithms, and use them to explore and understand the universe. DiRAC scientists play a major role in the construction of Rubin Observatory and the development of next-generation software tools through the LINCC program. Learn more at

New algorithm ensnares its first ‘potentially hazardous’ asteroid

An asteroid discovery algorithm — designed to uncover near-Earth asteroids for the
Vera C. Rubin Observatory’s upcoming 10-year survey of the night sky — has identified
its first “potentially hazardous” asteroid, a term for space rocks in Earth’s vicinity that
scientists like to keep an eye on.

The roughly 600-foot-long asteroid, designated 2022
SF289, was discovered during a test drive of the algorithm with the ATLAS survey in
Hawaii. Finding 2022 SF289, which poses no risk to Earth for the foreseeable future,
confirms that the next-generation algorithm, known as HelioLinc3D, can identify near-
Earth asteroids with fewer and more dispersed observations than required by today’s

Read full article here.

Big Data in the Night Sky

In conversation with James Davenport and 2022 DiRAC Research Prize recipients read more about Vera C. Rubin Observatory and important role of the scientists at the UW’s DiRAC Institute.

Astronomers discover a rare ’black widow’ binary, with the shortest orbit yet

In partnership with the news team at the Massachusetts Institute of Technology, the UW News office has posted a story about a rare and mysterious star system discovered by a team of astronomers and reported in a paper published this morning in Nature. The researchers report that the system appears to be a “black widow binary” — consisting of a rapidly spinning neutron star, or pulsar, that is circling and slowly consuming a smaller companion star, just as its arachnid namesake does to its mate.

Space Grant Summer Research – Apply now!

Washington state’s NASA Space Grant program at the UW invites you, as a faculty member conducting research in a STEM area, to participate our 2022 Summer Undergraduate Research Program (SURP).  The application period for students closes on Friday, April 8, 2022.

SURP is an excellent way to extend your summer funding through WA Space Grant’s contribution of half of the selected student’s award payment.  Faculty contribution per student is $2,750 full-time and $1,375 part-time.

If you already have a student working with you, we encourage you to apply for the program along with that student.  If you are looking for new students, you can apply and we will help to match you with a qualified undergraduate.

Through SURP, WA Space Grant seeks to increase research opportunities for undergraduates on NASA-related STEM projects, and we particularly welcome applications from students with traditionally marginalized genders and from underrepresented minoritized communities.  UW undergraduate students in good academic standing who are interested in research in science, technology, engineering or mathematics fields are eligible to apply. Applicants must be U.S. citizens.

The faculty request form is available at

The student application is also open through April 8, 2022.  Information for students can be found at:

Simulated SPHEREx spectra of asteroids and their implications for asteroid size and reflectance estimation

In January 2022, published paper by Zeljko Ivezić, Vedrana Ivezić, Moeyens Joachim

DiRAC members Joachim Moeyens and Zeljko Ivezić, aided by a DiRAC guest researcher Vedrana Ivezić, led a multi-institutional team of scientists who produced and analyzed simulated SPHEREx spectra of asteroids. 

SPHEREx is a 2-year NASA space mission scheduled for launch in less than 3 years. SPHEREx will deliver the first all-sky spectral survey at about 100 spectral channels in the infrared wavelength range 0.8-5.0 micron. The team estimated that SPHEREx dataset will be transformative: high-quality spectra will be obtained for close to 10,000 asteroids, representing an increase over our current sample size by more than an order of magnitude. 

With its additional LSST expertise, DiRAC will be well positioned to lead cutting-edge studies of asteroid taxonomy and photometric variability, and thus contribute to our understanding of the formation and evolution of our SolarSystem. 

ADS: Simulated SPHEREx spectra of asteroids and their implications for asteroid size and reflectance estimation

Supernova Siblings and their Parent Galaxies in the ZTF Bright Transient Survey

Published paper by Melissa Graham

Supernovae are the explosions of stars that can be seen across vast distances, appearing as new bright points of light in optical images of the sky, even when the original star was far too faint to be detected.

When different types of stars explode (e.g., low-mass and high-mass) they cause supernovae with a variety of characteristics (e.g., brightness, color, duration). When two or more supernovae (explosions of stars) occur in the same galaxy, we say they have the same “parent galaxy” and are “sibling supernovae”. The characteristics of sibling supernovae can thus be compared knowing that, since they have the same distance from Earth and come from similar environments, any differences between them are more likely to be related to the type of star that exploded. Sibling supernovae are thus very useful for obtaining a better understanding of both supernovae and their parent galaxies.

Since the average supernova rate for a Milky Way-type galaxy is just one per century, a large imaging survey is required to discover an appreciable sample of sibling supernovae. In this paper we present 10 sibling supernovae in 5 parent galaxies from the wide-field Zwicky Transient Facility (ZTF).

For each of these families we analyze the supernova’s location within the parent galaxy, finding agreement with expectations that supernovae from more massive stars are found nearer to their parent galaxy’s core, and in regions of more active star formation.

We also present an analysis of the relative rates of core collapse and thermonuclear sibling supernovae, finding a significantly lower ratio than past samples due to the unbiased nature of the ZTF.

ADS: Supernova Siblings and their Parent Galaxies in the Zwicky Transient Facility Bright Transient Survey


Melissa Graham currently works for Rubin Observatory as the Lead Community Scientist for the Community Engagement Team and as a Science Analyst for the Data Management team. Her main research focus is supernovae, especially those of Type Ia.

Mapping the “Cosmic Web”

A tenet of modern cosmology is the existence of the “cosmic web”, a vast filamentary structure formed via the collapse of matter due to gravity. This structure is ubiquitous in cosmological simulations yet challenging to observe due to its diffuse nature.

Recently, a new technique was developed which is inspired by the growth and movement of Physarum polycephalum slime mold to map the cosmic web of a low redshift (z < 0.01) sub-sample of the SDSS spectroscopic galaxy catalog (Burchet et al. 2020Elek et al. 2020). However, this limited volume limits the statistics and observational techniques that can be applied to this slime mold generated density field.

Matthew Wilde, UW graduate student, applied this algorithm to the classic SDSS and eBOSS surveys which expands the volume mapped to  z < 0.5. The slime mold density map shown in the accompanying image was recently released as a value added catalog (VAC) and released by the SDSS DR17 team (Abdurro’uf et al. 2021, Wilde et al. in prep.), and will allow astronomers a new way to explore the cosmic web. Applications of this density map include constraining the role of environment on galaxy evolution and the role of galactic feedback, more efficient follow up observing strategies for gravitational wave targets, and interesting tests of cosmological constants and dark matter candidates.