Interstellar comet 2I/Borisov as seen by MUSE: C$_2$, NH$_2$ and red CN detections

Michele T. Bannister; Cyrielle Opitom; Alan Fitzsimmons; Youssef Moulane; Emmanuel Jehin; Darryl Seligman; Philippe Rousselot; Matthew M. Knight; Michael Marsset; Megan E. Schwamb; Aurélie Guilbert-Lepoutre; Laurent Jorda; Pierre Vernazza; Zouhair Benkhaldoun

paper

Interstellar comet 2I/Borisov as seen by MUSE: C $_{2}$ , NH $_{2}$ and red CN detections

arXiv:2001.11605

Abstract

We report the clear detection of C $_{2}$ and of abundant NH $_{2}$ in the first prominently active interstellar comet, 2I/Borisov. We observed 2I on three nights in November 2019 at optical wavelengths 4800--9300 Åwith the Multi-Unit Spectroscopic Explorer (MUSE) integral-field spectrograph on the ESO/Very Large Telescope. These data, together with observations close in time from both 0.6-m TRAPPIST telescopes, provide constraints on the production rates of species of gas in 2I's coma. From the MUSE detection on all epochs of several bands of the optical emission of the C $_{2}$ Swan system, a rich emission spectrum of NH $_{2}$ with many highly visible bands, and the red (1-0) bandhead of CN, together with violet CN detections by TRAPPIST, we infer production rates of $Q$ (C $_{2}$ ) = $1.1 \times 1 0^{24}$ mol s $^{- 1}$ , $Q$ (NH $_{2}$ ) = $4.8 \times 1 0^{24}$ mol s $^{- 1}$ and $Q$ (CN) = $(1.8 \pm 0.2) \times 1 0^{24}$ mol s $^{- 1}$ . In late November at 2.03~au, 2I had a production ratio of C $_{2}$ /CN $= 0.61$ , only barely carbon-chain depleted, in contrast to earlier reports measured further from the Sun of strong carbon-chain depletion. Thus, 2I has shown evolution in its C $_{2}$ production rate: a parent molecule reservoir has started sublimating. At $Q$ (NH $_{2}$ )/ $Q$ (CN) = 2.7, this second interstellar object is enriched in NH $_{2}$ , relative to the known Solar System sample.

5 figures. Submitted to AAS Journals

Interstellar comet 2I/Borisov as seen by MUSE: C $_{2}$ , NH $_{2}$ and red CN detections

Abstract

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Interstellar comet 2I/Borisov as seen by MUSE: C2​, NH2​ and red CN detections

Abstract

References in corpus (2)

Cited by in corpus (8)

Interstellar comet 2I/Borisov as seen by MUSE: C $_{2}$ , NH $_{2}$ and red CN detections