Searching For Water Ice In The Coma Of Interstellar Object 2I/Borisov

Comparison between the spectrum of 2I and those of Solar System comets and asteroids. The spectrum of C/2013 US10 is taken from Protopapa et al. (2018), the spectrum of 6P/d’Arrest and is from Yang et al. (2009) and three asteroid spectral classes are taken from DeMeo et al. (2009).

Interstellar Objects (ISO) passing through our Solar System offer a rare opportunity to probe the physical and chemical processes involved in solid body and planet formation in extrasolar systems.

The main objective of our study is to search for diagnostic absorption features of water ice in the near infrared (NIR) spectrum of the second interstellar object 2I/2019 Q4 (Borisov) and compare its ice features to those of the Solar system icy objects. We observed 2I in the NIR on three separate occasions.

The first observation was made on 2019 September 19 UT using the SpeX spectrograph at the 3-m IRTF and again on September 24 UT with the GNIRS spectrograph at the 8-m GEMINI telescope and the last observation was made on October 09 UT with IRTF. The spectra obtained from all three nights appear featureless. No absorption features associated with water ice are detected. Spectral modeling suggests that water grains, if present, comprise no more than 10% of the coma cross-section.

The comet consistently exhibits a red D-type like spectrum with a spectral slope of about 6% per 100nm, which is similar to that of 1I/'Oumuamua and is comparable to Solar system comets.

Bin Yang, Michael S. P. Kelley, Karen J. Meech, Jacqueline V. Keane, Silvia Protopapa, Schelte J. Bus
(Submitted on 11 Dec 2019)

Comments: 5 pages, 4 figures, accepted for publication in A&A Letter
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:1912.05318 [astro-ph.EP] (or arXiv:1912.05318v1 [astro-ph.EP] for this version)
Submission history
From: Bin Yang
[v1] Wed, 11 Dec 2019 14:02:13 UTC (3,180 KB)
https://arxiv.org/abs/1912.05318
Astrobiology, Astrochemistry

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