The interstellar comet 2I/Borisov which is currently visiting our solar system is harbouring water that came from another star system, a study has found.
The findings suggest that water-rich comets are not unique to the Solar System and that other star systems likely formed through similar processes.
By extension, the universe is likely to contain other water-harbouring, Earth-like worlds which have the potential to support extraterrestrial life.
On October 10, experts announced that they had found that 2I/Borisov had come from a twin star system dubbed ‘Kruger 60’ that lies 13 light years away.
Borisov — named after the Crimean astronomer who discovered it — will pass within around 177,000 miles (285,000 kilometres) of the Earth in early December this year.
It is trailing behind it a 100,000 mile-long tail of dust, which is released as the comet melts in the Sun’s glare.
After this, it will head back out towards interstellar space, passing Jupiter around the middle of 2020.
2I/Borisov is the second-known visitor from outside our solar system — joining the cigar-shaped asteroid 1I/’Oumuamua, which was detected on October 19, 2017.
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The interstellar comet 2I/Borisov, pictured, which is currently visiting our solar system is harbouring water that came from another star system, a study has found
Astronomer Adam McKay of NASA’s Goddard Space Flight Center in Maryland and colleagues used the Astrophysical Research Consortium Telescope in New Mexico to analyse 2I/Borisov using so-called spectroscopic observations.
When light from our sun hits the comet, some is absorbed and some is reflected — depending on the elements and compounds in the cosmic body.
By studying the spectra of the light received from 2I/Borisov’s gas trail, scientists can thus determine the composition of the materials that make up the comet.
McKay and colleagues found an absorption line in the spectra taken from the comet that is consistent with water — with the strength of such suggesting that water is coming off of 2I/Borisov at a rate of around 113 septillion litres of water per second.
‘Comets have a primitive volatile composition that is thought to reflect the conditions present in their formation region in the protosolar disc,’ the researchers wrote in their paper.
‘This makes studies of cometary volatiles powerful for understanding the physical and chemical processes occurring during planet formation.’
‘Comet 2I/Borisov provides an opportunity to sample the volatile composition of a comet that is unambiguously from outside our own Solar System, providing constraints on the physics and chemistry of other protostellar discs,’ they added.
Comets seen in our solar system are typically also water-rich — with experts believing that much of the Earth’s water was deposited on our planet by comets.
Modelling the size of the active water-releasing area on the comet, the researchers predict an area of around 0.65 square miles (1.7 square kilometres) — a proportion of 2I/Borisov’s whole that is on par with the make-up of comets in the solar system.
The latest findings suggest that water-rich comets are not unique to the Solar System and that other star systems likely formed through similar processes
Other spectroscopic analyses have also found that Borisov is releasing diatomic carbon and cyanide — substances that are also common in comets orbiting the Sun.
Put together, the findings suggest that comets from elsewhere in the universe are likely very similar to those we have seen in our own cosmic neighbourhood — suggesting that the conditions that formed our Solar System are not unique.
Furthermore, this raises the likelihood of their being other, water-harbouring, Earth-like planets — which could potentially also have supported the development of life.
The full findings of the research are being prepared for submission in The Astrophysical Journal Letters.
A pre-print of the article, which has not yet been peer-reviewed, can be read on the arXiv repository.
2I/Borisov is the second-known visitor from outside our solar system — joining the cigar-shaped asteroid 1I/’Oumuamua, which was detected on October 19, 2017
On October 10, experts announced that they had found that 2I/Borisov had come from a twin star system dubbed ‘Kruger 60’, pictured in an artist’s impression, that lies 13 light years away
