The carbon monoxide-rich interstellar comet 2I/Borisov

Abstract

Interstellar comets offer direct samples of volatiles from distant protoplanetary disks. 2I/Borisov is the first notably active interstellar comet discovered in our solar system[1]. Comets are condensed samples of the gas, ice, and dust that were in a star's protoplanetary disk during the formation of its planets and inform our understanding on how chemical compositions and abundances vary with distance from the central star. Their orbital migration moves volatiles[2], organic material, and prebiotic chemicals in their host system[3]. In our solar system, hundreds of comets have been observed remotely, and a few have been studied up close by space missions[4]. However, knowledge of extrasolar comets has been limited to what could be gleaned from distant, unresolved observations of cometary regions around other stars, with only one detection of carbon monoxide[5]. Here we report that the coma of 2I/Borisov contains significantly more CO than H2O gas, with abundances of at least 173%, more than three times higher than previously measured for any comet in the inner (<2.5 au) solar system[4]. Our ultraviolet observations of 2I/Borisov provide the first glimpse into the ice content and chemical composition of the protoplanetary disk of another star that is substantially different from our own.

References in corpus (13)

• The ancient heritage of water ice in the solar system
• Initial characterization of interstellar comet 2I/Borisov
• Detection of exocometary CO within the 440 Myr-old Fomalhaut belt: a similar CO+CO${}_2$ ice abundance in exocomets and Solar System comets
• The Natural History of 'Oumuamua
• Evolution of CO${}_2$, CH${}_4$, and OCS abundances relative to H${}_2$O in the coma of comet 67P around perihelion from Rosetta/VIRTIS-H observations
• Detection of CN gas in Interstellar Object 2I/Borisov
• The Nucleus of Interstellar Comet 2I/Borisov
• The Fourth Positive System of Carbon Monoxide in the Hubble Space Telescope Spectra of Comets
• Pre-discovery Activity of New Interstellar Comet 2I/Borisov Beyond 5 AU
• Detection of a Water Tracer in Interstellar Comet 2I/Borisov
• High resolution optical spectroscopy of the ${\mathrm{N}}_2$-rich comet C/2016 R2 (PanSTARRS)
• A search for the origin of the interstellar comet 2I/Borisov
• Interstellar comet 2I/Borisov as seen by MUSE: C${}_2$, NH${}_2$ and red CN detections

Cited by in corpus (4)

• CO Depletion in Protoplanetary Disks: A Unified Picture Combining Physical Sequestration and Chemical Processing
• Outburst and Splitting of Interstellar Comet 2I/Borisov
• Coma Anisotropy and the Rotation Pole of Interstellar Comet 2I/Borisov
• "In-System" Fission-Events: An Insight into Puzzles of Exoplanets and Stars?