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Is interstellar Comet Borisov breaking apart as it leaves our solar system?

NASA's Hubble Space Telescope captured this view of the interstellar object Comet 2I/Borisov on Oct. 12, 2019.
NASA's Hubble Space Telescope captured this view of the interstellar object Comet 2I/Borisov on Oct. 12, 2019.
(Image: © NASA/ESA/D. Jewitt (UCLA))

It's tough being in a new environment, even for comets. According to recent observations, interstellar Comet Borisov may be having outbursts triggered by flying through our solar system and past our sun.

The comet, now dubbed Borisov, first caught skywatchers' attention in late August 2019. Repeated observations of the object traced its trajectory, and astronomers determined that its strange path meant that the comet could only have come from beyond our solar system and was just passing through our neighborhood.

This month, astronomers checking in on the object found that something weird was happening. A team based in Poland reported that twice in March so far, Comet Borisov had brightened up. "This behavior is strongly indicative of an ongoing nucleus fragmentation," they wrote in a note describing the new observations.

Related: Interstellar comet: Here's why it's got scientists so pumped up

Such a phenomenon would be caused by Borisov's approach toward the sun. That's been a possibility that scientists have considered since its close flyby of the sun in December. Like all comets, Borisov is a hunk of icy debris, so passing by the sun causes interactions with that ice.

Borisov was an exciting discovery because — unlike 'Oumuamua, the first interstellar object that scientists spotted — astronomers identified the object with plenty of time, more than a year, to watch and study its journey through our solar system.

It's precisely observations like these new ones that scientists hoped that long period of visibility would permit.

Email Meghan Bartels at mbartels@space.com or follow her @meghanbartels. Follow us on Twitter @Spacedotcom and on Facebook. 

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  • Torbjorn Larsson
    Admin said:
    It's tough being in a new environment, even for comets. According to recent observations, interstellar Comet Borisov may be having outbursts triggered by flying past our sun.

    Is interstellar Comet Borisov breaking apart as it leaves our solar system? : Read more

    More (albeit weak) validation of the interstellar object hypothesis. ""For Solar System comets, it is known that dynamically new comets are 10 times more likely to disintegrate than short-period comets, presumably due to their pristine state and weaker structural strength," wrote researchers led by Quanzhi Ye from the University of Maryland last year."

    https://www.sciencealert.com/interstellar-comet-2i-borisov-seems-to-have-come-here-only-to-die ]
    Reply