#comet borisov

[kreuzaderny]

2I/Borisov: A Remarkably Pristine Interstellar Comet

The beauty of comet 2I/Borisov, the second interstellar object discovered in our Solar System, is that it looks and acts more or less like, well, an interstellar comet, without the puzzling characteristics of its predecessor, the still controversial ‘Oumuamua. 2I/Borisov’s cometary nature is clear in the latest observations from the European Southern Observatory’s Very Large Telescope, data from which also tell us that this is one of the most undisturbed relics of a circumstellar disk ever found. Scientists believe it never passed close to any star before its 2019 passage by the Sun.

[joerojasburke]

Oct 22, 2018: #Borisov & #Oumuamua make close approach to each other at 8.5 AU

via @tony873004, who says:

“From Borisov's point of view, in the last 2 years it was visited by an interstellar object and a solar system”

[don-lichterman]

NASA Video Shows Comet Borisov Visiting From Outside Our Solar System

NASA Video Shows Comet Borisov Visiting From Outside Our Solar System

NASA’s Hubble telescope has captured the interstellar visitor Comet Borisov to our solar system and shared its movement as a runaway point of light in a time-lapse video. The agency said that it “was a rocky visit”. Discovered by amateur astronomer Gennady Borisov in 2019, it is the first confirmed comet to enter our solar system from outside our Sun’s influence. Comet Borisov is the only second…

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[kreuzaderny]

Interstellar Comet Borisov Reveals Its Chemistry and Possible Origins

On Aug. 30, 2019, when amateur astronomer Gennady Borisov gazed upward with his homemade telescope, he spotted an object moving in an unusual direction. Now called 2I/Borisov, this runaway point of light turned out to be the first confirmed comet to enter our solar system from some unknown place beyond our Sun’s influence. Astronomers everywhere rushed to take a look with some of the most powerful instruments in the world, hoping to learn as much as they could about the mysterious visitor.

Now, thanks to observations with NASA’s Hubble Space Telescope and the National Radio Astronomy Observatory’s Atacama Large Millimeter/submillimeter Array (ALMA), astronomers have figured out that 2I/Borisov has an unusual composition. Specifically, it has a higher concentration of carbon monoxide than any comet seen at a similar distance; that is, within about 200 million miles (300 million kilometers) of the Sun.

This suggests to scientists that the comet could have formed around a red dwarf — a smaller, fainter type of star than the Sun — though other kinds of stars are possible. Another idea is that 2I/Borisov could be a carbon monoxide-rich fragment of a small planet.

[kreuzaderny]

Water production rates and activity of interstellar comet 2I/Borisov

 We observed the interstellar comet 2I/Borisov using the Neil Gehrels-Swift Observatory's Ultraviolet/Optical Telescope. We obtained images of the OH gas and dust surrounding the nucleus at four epochs spaced before and just after perihelion (-2.56 AU to 2.03 AU). Water production rates increased steadily before perihelion from (7.0±1.5)×1026 molecules s−1 on Nov. 1, 2019 to (10.7±1.2)×1026 molecules s−1 on Dec. 1. This rate of increase in water production rate is slower than that of most Jupiter-family comets and quicker than most dynamically new comets. After perihelion, the water production rate decreased rapidly to (4.9±0.9)×1026 molecules s−1 on Dec. 21. Our sublimation model constrains the minimum radius of the nucleus to 0.37 km, and indicates an active fraction of at least 55% of the surface. A(0)fρ calculations show variation between 90 and 106 cm with a slight trend peaking before the perihelion, lower than previous and concurrent published values. The observations confirm that 2I/Borisov is carbon-chain depleted and enriched in NH2 relative to water.

[ianmiller42]

Space News

There were two pieces of news relating to space recently. Thirty years ago we knew there were stars. Now we know there are exoplanets and over 4,000 of them have been found. Many of these are much larger than Jupiter, but that may be because the bigger they are, the easier it is to find them. There are a number of planets very close to small stars for the same reason. Around one giant planet…

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[kreuzaderny]

The Gran Telescopio Canarias (GTC) obtains the visible spectrum of C/2019 Q4 (Borisov), the first confirmed interstellar comet

Miquel Serra Ricart points out that "the image of C/2019 Q4 shows a cometary object, with well-defined coma and tail". Julia de León adds that "the spectrum of this object is similar to those of Solar System comets and this indicates that their composition must be similar".