The available evidence suggests that there is a lot of water out there in the universe, beyond our Solar System. Detecting it and studying it, however, is not an easy task … unless that water comes to us. And so it seems to be the case with the newly detected interstellar comet Borisov.
According to a new analysis of 2I / Borisov (or simply Borisov), sent to The Astrophysical Journal Letters and uploaded to the arXiv pre-print source, this comet is giving off water vapor as it enters our neighborhood. This provides information about the comet’s nucleus, volatile elements and the compounds it is launching, in addition to the circumstellar disk where it originated.
“The discovery of Borisov is a unique opportunity to study the volatile composition of a comet that comes unequivocally from outside our solar system, and thus have an idea of the physics and chemistry of exoplanetary systems,” say the scientists in the study.
We know that comets in the Solar System are usually rich in water; In fact, it is believed that much of the water that Earth has today came from comets and asteroids. With that in mind, Adam McKay and his colleagues from NASA’s Goddard Space Flight Center made spectroscopic observations of the comet. Using the ARCES high-resolution instrument, mounted on the ARC Telescope in New Mexico, they took two spectra with 1,800-second exposure.
Borisov does not emit his own light but is illuminated by the Sun. The spectra break the light from the comet to its constituent wavelengths. And since different elements and compounds emit and absorb specific wavelengths, this allowed researchers to find out the chemical composition of the gas through which the light was being filtered.
2I / Borisov is the second known interstellar visitor. The first was Oumuamua (in 2017), a strange cigar-shaped object that raised all kinds of theories about its nature and origin.
In both spectra, the team observed an absorption line consistent with the presence of water. Based on the strength of this line, the interstellar comet is sublimating an amount of water similar to that of the comets of our own system. Also, a simple model determined that the active water area is about 1.7 square kilometers.
Other spectroscopic analyzes carried out in a couple of months since the comet’s discovery have found that Borisov also produces cyanide and diatomic carbon – two other substances common in solar system comets.
The team is cautious in highlighting that their results are based on a single model and that subsequent observations are necessary for the confirmation of their findings.
For now, everything indicates that the comet looks quite familiar, and that is amazing because it means that the formation conditions of our solar system are not unique. This, extrapolated, means that there could be a lot of planets like ours out there.
It is less than two months before Borisov reaches his perihelion – his closest approach to the Sun – on December 8. You lie so much, and as it continues to grow in brightness for astronomers, we will wait to see what new information is revealed about this interstellar visitor.