Interstellar comet 3I/ATLAS tail changing as it zooms through solar system
The Gemini South telescope in Chile captured new images showing a growing tail on the interstellar comet 3I/ATLAS.
Interstellar comet 3I/ATLAS as seen by Rubin Observatory
FILE VIDEO: The recently discovered interstellar comet 3I/ATLAS was spotted by the new NSF-DOE Vera C. Rubin Observatory in Chile.
Astronomers continue to track the third-ever discovered interstellar object, comet 3I/ATLAS, using powerful telescopes and spacecraft as it moves through our cosmic neighborhood.
Just last week, the Gemini South telescope in Chile captured new images showing a growing tail on the comet and providing new details of its color and composition.
Comet 3I/ATLAS was first spotted on July 1 by the NASA-funded Asteroid Terrestrial-impact Last Alert System (ATLAS), also in Chile. Only two previous interstellar objects have been tracked and documented through our solar system, Oumuamua in 2017 and 2I/Borisov in 2019.
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The U.S. has other facilities in Chile also tracking the comet, including the brand-new Vera C. Rubin Observatory and the International Gemini Observatory.
On Aug. 27, Gemini’s Multi-Object Spectrograph was used to take multicolor images of comet 3I/ATLAS.
Comet 3I/ATLAS streaks across a dense star field in this image captured by the Gemini Multi-Object Spectrograph (GMOS) on Gemini South at Cerro Pachón in Chile, one half of the International Gemini Observatory, partly funded by the U.S. National Science Foundation (NSF) and operated by NSF NOIRLab. This image is composed of exposures taken through four filters — red, green, blue and ultraviolet. As exposures 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 colorful streaks in the final image. (International Gemini Observatory/NOIRLab/NSF/AURA/Shadow the Scientist / FOX Weather)
According to the National Science Foundation NOIRLab, which operates the observatory, the images show a tail spinning across about 1/120th of a degree in the sky.
"These features are significantly more extended than they appeared in earlier images of the comet, showing that 3I/ATLAS has become more active as it travels through the inner Solar System," according to NOIRLab.
The tail is significantly more pronounced compared to the image below taken by the Gemini North telescope in Hawaii in July.
Comet 3I/ATLAS is captured in this image by the Gemini North telescope. The incredible sensitivity of Gemini North's Multi-Object Spectrograph (GMOS-N) reveals the comet’s compact coma — a cloud of gas and dust surrounding its icy nucleus. (International Gemini Observatory/NOIRLab/NSF/AURA/K. Meech (IfA/U. Hawaii) Image Processing: Jen Miller & Mahdi Zamani (NSF NOIRLab) / FOX Weather)
In addition to new photos of this unusual comet, the team also obtained new measurements of its color and composition, important for understanding how this object is changing as it nears the Sun.
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"The primary objectives of the observations were to look at the colors of the comet, which provide clues to the composition and sizes of the dust particles in the coma, and to take spectra for a direct measure of the chemistry," University of Hawai‘i Institute for Astronomy Karen Meech said in a statement. "We were excited to see the growth of the tail, suggesting a change in the particles from the previous Gemini images, and we got our first glimpse of the chemistry from the spectrum."
Recent observations by NASA’s James Webb Space Telescope found some unusual chemical signatures on 3I/ATLAS, including a coma dominated by carbon dioxide, the "highest ever observed in a comet."
Later in September, the interstellar comet will dip behind the Sun. When it emerges in November, more observations with Gemini are planned.