noirlab2532 — Photo release
The Shadow the Scientists community observing program took the public on a second tour of the famous interstellar visitor with live observations from the Gemini North Telescope control room in Hawaii.
December 12, 2025
Gemini North has captured new images of comet 3I/ATLAS after it re-emerged from behind the Sun as it exited the solar system. The data was collected during a Shadow the Scientists session, a unique outreach initiative that invites students around the world to join researchers as they observe the Universe on the world’s most advanced telescopes.
On November 26, 2025, scientists used the Gemini Multi-Object Spectrograph (GMOS) on Gemini North at Maunakea in Hawai’i to obtain images of the third interstellar object ever detected, Comet 3I/ATLAS. The new observations reveal how the comet changed after getting closer to the Sun. Gemini North is one half of the International Gemini Observatory, partly funded by the US National Science Foundation (NSF) and managed by NSF NOIRLab.
After emerging behind the Sun, 3I/ATLAS reappeared in the sky near Zaniah, a triple star system located in the constellation Virgo. These observations were taken as part of a public outreach initiative organized by NSF NOIRLab in collaboration with Shadow the Scientists, an initiative created to connect the public with scientists to inspire them to participate in authentic science experiences, such as astronomy observing experiments on world-class telescopes. [1]. The science program was led by Eureka Scientific Research Scientist Bryce Bolin.
This image is composed of exposures taken through four filters: blue, green, orange and red. As the images are taken, the comet remains fixed in the center of the telescope’s field of view. However, the positions of the background stars change relative to the comet, causing them to appear as colored streaks in the final image.
In earlier images of the comet, captured during a Shadow the Scientists session held at Gemini South in Chile, it appears to have a red tint. However, in the new image released today, it appears to have a slight greenish glow. This is due to light emitted by gases in the comet’s coma that evaporate as the comet heats up, including diatomic carbon (C2), a highly reactive molecule composed of two carbon atoms that emits light at green wavelengths.
What remains unknown is how the comet will behave when it leaves the Sun’s vicinity and cools. Many comets respond late to the Sun’s heat because of the time it takes for the heat to make its way inside the comet. A delay can activate the evaporation of new chemicals or trigger a comet explosion. Gemini will continue to monitor the comet as it leaves the solar system and detect changes in its gas composition and explosion behavior.
This collaboration with Shadow the Scientists builds on NOIRLab’s tradition of combining cutting-edge science and public engagement, ensuring that remarkable cosmic events are shared as widely as possible. By directly involving learners in observing sessions and collecting data [2]Programs like this not only advance knowledge, but also inspire the next generation of explorers.
“Sharing an observing experience in some of the best conditions available gives the public a true first-hand view of our interstellar visitor,” Bolin said. “Allowing the public to see what we do as astronomers and how we do it also helps demystify the scientific and data collection process, adding transparency to our study of this fascinating object.”
Remarks
[1] The Shadow the Scientists initiative is made possible through the Creating Equity in STEAM (CrEST) program at the University of California, Santa Cruz, as well as support from the Heising-Simons Foundation.
[2] All data from the observing session are available for download from the Gemini archives.
More information
NSF NOIRLab, the U.S. National Science Foundation’s center for ground-based optical-infrared astronomy, operates the Gemini International Observatory (a facility of NSF, NRC-Canada, ANID-Chile, MCTIC-Brazil, MINCyT-Argentina, and KASI-Republic of Korea), the NSF Kitt Peak National Observatory (KPNO), the NSF Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC) and NSF-DOE Vera C. Rubin Observatory (in cooperation with DOE’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the NSF and is headquartered in Tucson, Arizona.
The scientific community is honored to have the opportunity to conduct astronomical research on I’oligam Du’ag (Kitt Peak) in Arizona, on White Mountain in Hawaii, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and recognize the very important cultural role and respect for I’oligam Du’ag to the Tohono O’odham Nation, and White Mountain At real people (Native Hawaiians).
Contacts
Bryce Bolin
Scientific researcher
Eureka Scientific, Inc.
Email: bolin.astro@gmail.com
Josie Fenske
Public Information Officer
NSF NOIRLab
Email: josie.fenske@noirlab.edu
