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
WHAT IS 2I/BORISOV?
2I/Borisov is a comet that came from outside the solar system.
It is believed to have a core that is around 0.9–4.1 miles (1.4–6.6 kilometres) in diameter.
The comet was spotted by amateur astronomer Gennady Borisov from Crimea’s MARGOT observatory on August 30, 2019.
It will make its closest pass to the Sun on December 8, 2019 — but will not get close to any of the planets in the solar system.
2I/Borisov will leave the solar system in the direction of the constellation of Telescopium.
According to Polish researchers, it likely originated from the binary red dwarf star system Kruger 60.
The comet is only the second interstellar visit to have been spotted.
The first was the cigar-shaped asteroid 1I/’Oumuamua, which was detected on October 19, 2017.
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
WHAT IS ‘OUMUAMUA AND WHAT DO WE KNOW ABOUT IT?
A cigar-shaped asteroid named ‘Oumuamua sailed past Earth at 97,200mph (156,428km/h) in October.
It was first spotted by a telescope in Hawaii on 19 October, and was observed 34 separate times in the following week.
It is named after the Hawaiian term for ‘scout’ or ‘messenger’ and passed the Earth at about 85 times the distance to the moon.
It was the first interstellar object seen in the solar system, and it baffled astronomers.
Initially, it was thought the object could be a comet.
However, it displays none of the classic behaviour expected of comets, such as a dusty, water-ice particle tail.
The asteroid is up to one-quarter mile (400 meters) long and highly-elongated – perhaps 10 times as long as it is wide.
That aspect ratio is greater than that of any asteroid or asteroid observed in our solar system to date.
But the asteroid’s slightly red hue — specifically pale pink — and varying brightness are remarkably similar to objects in our own solar system.
Around the size of the Gherkin skyscraper in London, some astronomers were convinced it was piloted by aliens due to the vast distance the object traveled without being destroyed – and the closeness of its journey past the Earth.
Alien hunters at SETI – the Search for Extra-terrestrial Intelligence based at Berkeley University, California said there was a possibility the rock was ‘an alien artefact’.
But scientists from Queen’s University Belfast took a good look at the object and said it appears to be an asteroid, or ‘planetesimal’ as originally thought.
Researchers believe the cigar-shaped asteroid had a ‘violent past’, after looking at the light bouncing off its surface.
They aren’t exactly sure when the violent collision took place, but they believe the lonely asteroid’s tumbling will continue for at least a billion years.