The carbon monoxide-rich interstellar comet 2I/Borisov

Bodewits, Dennis; Noonan, John; Feldman, P. D.; Bannister, Michele; Farnocchia, Davide; Harris, Walter M.; Li, J.-Y.; Mandt, K.; Parker, J. W.; Xing, Zexi

doi:10.1038/s41550-020-1095-2

Cited by 85 publications

(76 citation statements)

References 30 publications

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“…6 ) makes it the first obviously active extrasolar comet ever detected in our Solar system. In addition, this comet is rich in supervolatile CO 7,8 , regardless of its small nucleus 9,10 , which indicates that the nucleus of 2I/Borisov is likely to be pristine.…”

mentioning

confidence: 96%

Compact pebbles and the evolution of volatiles in the interstellar comet 2I/Borisov

Yang

Cordiner

et al. 2021

Nat Astron

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The interstellar traveler, 2I/Borisov, is the first clearly active extrasolar comet, ever detected in our Solar system. We obtained high-resolution interferometric observations of 2I/Borisov with the Atacama Large Millimeter/submillimeter Array (ALMA), and multi-color optical observations with the Very Large Telescope (VLT) to gain a comprehensive understanding of the dust properties of this comet. We found that the dust coma of 2I/Borisov consists of compact "pebbles" of radii exceeding ∼ 1 mm, suggesting that the dust particles have experienced compaction through mutual impacts during the bouncing collision phase in the protoplanetary disk. We derived a dust mass loss rate of > ∼ 200 kg s −1 and a dust-to-gas ratio > ∼ 3. Our long term monitoring of 2I/Borisov with VLT indicates a steady dust mass loss with no significant dust fragmentation and/or sublimation occurring in the coma. We also detected emissions from carbon monoxide gas (CO) with ALMA and derived the gas production rate of Q(CO) = (3.3 ± 0.8) × 10 26 s −1 . We found that the CO/H 2 O mixing ratio of 2I/Borisov changed drastically before and after perihelion, indicating the heterogeneity of the cometary nucleus, with components formed at different locations beyond the volatile snow-line with different chemical abundances. Our observations suggest that 2I/Borisov's home system, much like our own system, experienced efficient radial mixing from the innermost parts of its protoplanetary disk to beyond the frost line of CO.

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confidence: 96%

Compact pebbles and the evolution of volatiles in the interstellar comet 2I/Borisov

Yang

Cordiner

et al. 2021

Nat Astron

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“…While most cometary comae are dominated by H 2 O, several exceptions have been discovered recently, such as the 29P/Schwassmann-Wachmann 1 Comet (Ootsubo et al 2012), A&A 647, A127 (2021) C/2016 R2 (Pan-STARRS) Comet (Cochran & McKay 2018), and the first interstellar comet 2I/Borisov (Bodewits et al 2020;Cordiner et al 2020). Instead of H 2 O, in these cases, CO was found to be the dominant component.…”

Section: Introductionmentioning

confidence: 94%

Photodissociation branching ratios of¹²C¹⁶O from 110 500 to 113 045 cm⁻¹: first observation of the C(¹S) channel

Guan

Jiang

Zhang

et al. 2021

A&A

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Carbon monoxide (CO) is one of the most abundant molecular species in comets. Its photodissociation by the solar radiation in the vacuum ultraviolet (VUV) region produces excited atomic fragments C(1D), C(1S), and O(1D), which radiate at characteristic wavelengths when they decay to lower states. The fractional rate constants for generating these fragments from CO photodissociation under the entire range of the solar radiation field are key input values in modelling the observed atomic emission intensities from comets. In this study, the branching ratios of the four lowest dissociation channels C(3P)+O(3P), C(1D)+O(3P), C(3P)+O(1D), and C(1S)+O(3P) of the 12C16O photodissociation are measured in the VUV energy range between the threshold of producing the C(1S)+O(3P) channel (~110 500 cm−1) and the ionisation energy (IE) of 12C16O (~113 045 cm−1). We measured these ratios using the VUV time-slice velocity-map ion imaging apparatus. We observe a number of high Rydberg states in the aforementioned energy range, with most of them mainly producing ground C(3P) and O(3P) atomic fragments, and only a few of them producing a significant amount of excited C(1D) or O(1D) fragments. We also observe the excited C(1S) fragment from CO photodissociation and measured its branching ratio for the first time. Based on the photodissociation branching ratios measured in the current and previous studies, we are able to estimate the relative percentages of the excited atomic fragments C(1D), C(1S), and O(1D) from the solar photolysis of 12C16O below its IE. We discuss the implications for the photochemical modelling of the CO-dominated comet C/2016 R2 (Pan-STARRS).

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“…However, the chemistry of the ISO, particularly the isotopic ratios and abundances of volatiles may provide additional constraints on the ISO's possible system of origin, and the chemical differences between stellar systems more broadly. If an ISO is from a star from a class different from our own sun, we would expect it to exhibit different elemental abundances, expressed, for example in different relative abundances of volatile elements (e.g., Bodewits et al 2020 for I2/Borisov).…”

Section: Science Objectivementioning

confidence: 99%

Bridge to the stars: A mission concept to an interstellar object

Moore

Courville

Ferguson

et al. 2021

Planetary and Space Science

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The carbon monoxide-rich interstellar comet 2I/Borisov

Cited by 85 publications

References 30 publications

Compact pebbles and the evolution of volatiles in the interstellar comet 2I/Borisov

Compact pebbles and the evolution of volatiles in the interstellar comet 2I/Borisov

Photodissociation branching ratios of¹²C¹⁶O from 110 500 to 113 045 cm⁻¹: first observation of the C(¹S) channel

Bridge to the stars: A mission concept to an interstellar object

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The carbon monoxide-rich interstellar comet 2I/Borisov

Cited by 85 publications

References 30 publications

Compact pebbles and the evolution of volatiles in the interstellar comet 2I/Borisov

Compact pebbles and the evolution of volatiles in the interstellar comet 2I/Borisov

Photodissociation branching ratios of12C16O from 110 500 to 113 045 cm−1: first observation of the C(1S) channel

Bridge to the stars: A mission concept to an interstellar object

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Photodissociation branching ratios of¹²C¹⁶O from 110 500 to 113 045 cm⁻¹: first observation of the C(¹S) channel