An interstellar comet revealed
The big picture: Comet 2I/Borisov represents just the second-known interstellar object to make its way through our solar system, and it's astronomers' best chance so far to study a piece of a distant star system at close range.
- Even if it does turn out that the comet is just like those native to our solar system, it will show astronomers that other planetary systems light-years from our own likely formed in similar ways.
What they found: Unlike the strange cigar shape of the first interstellar object — named 'Oumuamua and seen in 2017 — 2I/Borisov has a pronounced dust tail and a reddish color that can be compared to other comets, according to the study.
- "In combination with what we have learned from peculiar `Oumuamua, it tells us that there may be a lot of diversity in other planetary systems and the formation of minor bodies," Piotr Guzik, one of the authors of the new study, told Axios via email.
- The team began its observations of the comet on Sept. 10, using the Gemini North Telescope in Hawaii and the William Herschel Telescope in Spain.
"This is a quick first look at the object and is showing what everyone has seen who has been observing this."— University of Hawaii astronomer Karen Meech, who did not take part in the study, told Axios via email
What to watch: Astronomers will be keeping a close eye on 2I/Borisov as long as it's visible from Earth.
- An earlier study submitted to The Astrophysical Journal Letters found cyanogen, a common molecule in solar system comets, in 2I/Borisov's atmosphere.
- However, the comet still isn't in the perfect position to be able to get a good look at its chemical signature yet.
- As the object gets closer — with its closest flyby of the Sun expected in early December — scientists should be able to piece together the chemical makeup of the comet's atmosphere and figure out just how familiar or alien it really is.