Almost two months since its discovery, astronomers continue to unlock the mysteries of our second interstellar visitor, Comet 2I/Borisov. The latest observations have revealed the first detection of water from this fascinating object.
In a paper available to read as a pre-print on ArXiv, American researchers have collected high-resolution observations of the comet and were able to detect oxygen emissions, a classic tracer for the presence of water, in the comet’s gas ejections. Armed with that, they were able to establish that the comet releases over 11,000 billion billion tons of water every second.
So far the only element that has been conclusively detected on the comet is cyanide. The ratio between the amount of cyanide to water release is between three and nine parts per thousand. This range veers from average for a typical comet to a slightly more active one. The comet is being constantly monitored from many observatories so these values will be further refined over the coming weeks.
Even if Borisov is a more active comet compared to the Solar System’s average, it is still in line with the evidence suggesting that despite not originating in the Solar System, it is not that different from other icy bodies that we have studied so far. This has important consequences, as it suggests that the formation mechanism for comets must be fairly similar across different star systems.
The comet was discovered on August 30 by amateur astronomer Gennady Borisov at the MARGO Observatory, Crimea. It was named after its discoverer, as tradition dictates, and has the prefix 2I as it’s the second interstellar object discovered in the Solar System after ‘Oumuamua, an asteroid discovered in 2017.
The nucleus is roughly 1 kilometer (0.6 miles) in diameter. Researchers have also observed the comet’s tail and its dusty atmosphere, also known as the coma. It's moving at a whopping 150,000 kilometers (93,000 miles) per hour and coming in at a very steep 40-degree angle with respect to the orbital plane of our planet. These factors were crucial to determining that the comet was traveling from outside the Solar System.
Comet Borisov is still heading towards the inner Solar System. Its closest point to the Sun will happen on December 8, when it will be roughly 300 million kilometers (190 million miles) away. That’s roughly twice the Earth-Sun distance.