Comet Borisov

comet

Also known as: 2I Borisov

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July 23, 2026

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Comet Borisov, also known as 2I Borisov, is an interstellar object discovered in 2019. It is the second such object observed entering our solar system, following 'Oumuamua in 2017. Like other comets, Borisov possesses a coma and tail, indicating the presence of volatile ices that sublimate when near the Sun. However, it exhibited higher abundances of carbon monoxide gas compared to other observed comets. Interstellar objects like Borisov are thought to be ejected from their home planetary systems during the early stages of planetary formation when giant planets migrate and scatter material.12

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interstellar object
Comets Borisov and ATLAS
The second interstellar object, Comet Borisov (also called 2I Borisov), was discovered by Russian amateur astronomer Gennady Borisov on August 30, 2019. Observations revealed a cometary coma and tail as well as an orbit showing an origin from outside the solar system. In many of its properties the comet…
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The second interstellar object, Comet Borisov (also called 2I Borisov), was discovered by Russian amateur astronomer Gennady Borisov on August 30, 2019. Observations revealed a cometary coma and tail as well as an orbit showing an origin from outside the solar system. In many of its properties the comet…
Read More