The carbon monoxide-rich interstellar comet 2I/Borisov

D. Bodewits; J. W. Noonan; P. D. Feldman; M. T. Bannister; D. Farnocchia; W. M. Harris; J. -Y. Li; K. E. Mandt; J. Wm. Parker; Z. Xing

doi:10.1038/s41550-020-1095-2

arXiv · 2004.08972

The carbon monoxide-rich interstellar comet 2I/Borisov

D. Bodewits·J. W. Noonan·P. D. Feldman·M. T. Bannister·D. Farnocchia·W. M. Harris·J. -Y. Li·K. E. Mandt·J. Wm. Parker·Z. Xing

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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.

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D. Bodewits, J. W. Noonan, P. D. Feldman, M. T. Bannister, D. Farnocchia, W. M. Harris, J. -Y. Li, K. E. Mandt, J. Wm. Parker, Z. Xing. 2020-04-19. The carbon monoxide-rich interstellar comet 2I/Borisov. https://doi.org/10.1038/s41550-020-1095-2

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