Gemini South Telescope Captures Interstellar Comet 3I/ATLAS
Interstellar visitors like Comet 3I/ATLAS provide astronomers with a rare opportunity to study objects from another solar system. Discovered on July 1st, the comet was entering the inner Solar System at about 4.5 astronomical units from the Sun. It is an active comet with an icy nucleus, warming as it approaches the Sun, releasing gas and dust to form a coma and tail.
3I/ATLAS is the third confirmed interstellar object after Oumuamua and Comet 2L/Borisov. These objects intrigue astronomers due to their trajectories, which will take them out of the Solar System, never to be seen again.
The new images of Comet 3I/ATLAS were captured by the Gemini South Telescope in Chile, an 8.1-meter optical/infrared telescope paired with the Gemini North Telescope in Hawaii. These telescopes are operated by the National Science Foundation's NOIRLab.
Interestingly, these images are not part of a dedicated scientific program but a public outreach initiative involving NOIRLab and Shadow the Scientists, aimed at connecting astronomers with the public.
On August 27, 2025, astronomers used the Gemini South's Gemini Multi-Object Spectrograph (GMOS) to capture deep images of Comet 3I/ATLAS, its coma, and tail. The images reveal the growth of the coma and tail compared to earlier images.
During the outreach initiative, members of the public and students from Hawaii and Chile joined a Zoom call with astronomers at Gemini South, allowing them to ask questions and follow observations in real time. Participants from Europe, New Zealand, and South America also joined.
Time-critical communication among the science team and observatory staff was prioritized during the session, providing public participants with an immersive experience in real-time astronomical observations.
Gemini South's Gemini Multi-Object Spectrograph (GMOS) captured the comet's spectrum, providing insights into its chemical composition. This helps astronomers understand the changes the comet undergoes as it traverses the inner Solar System.
Comet 3I/ATLAS is only the third confirmed interstellar object to visit our Solar System, offering a rare opportunity to study something from a distant star up close.