Oumuamua received tons of attention from astronomers once it was confirmed to be an interstellar object of unknown origins whizzing through our solar system. But just last Summer, a second interstellar object paid our solar system a visit: 2I/Borosov.
We don’t know much a bout 2I/Borosov except that it was an interstellar comet that had been discovered by an amateur astronomer. Perhaps unsurprisingly, more and more astronomers turned their telescopes toward the object when it became clear that there would only be a limited opportunity to observe it.
One of such telescopes to be used was the Atacama Large Millimeter/Sub-millimeter Array (ALMA), and with it, astronomers learned more about the comet’s composition. Of particular interest, the comet’s halo emitted more carbon monoxide than any other known comet in our solar system at a similar distance from Earth. This was later confirmed by NASA’s Hubble Space Telescope, and left many astronomers scratching their heads.
This discovery was important because it raised one of two potential questions about comets: 1) is comet chemical diversity more diverse than initially thought?; or 2) could this be our first official look at the potential chemical properties of another stellar system?
Whatever the case may be, astronomers think that in order for a comet like 2I/Borosov to port so much carbon monoxide, it would have needed to form far away from its host star. To put that into perspective using our own solar system, that means that it would have needed to form somewhere in the vicinity of the distance of Neptune from our own star.
It remains to be seen how 2I/Borosov got thrown out of its place of origin, but one thing’s certain: interstellar object discoveries are few and far in between, so astronomers will definitely want to take special advantage of opportunities just like this one to better understand the universe around us.