Activity of the first interstellar comet 2I/Borisov around perihelion: results from Indian observatories

ABSTRACT Comet 2I/Borisov is the first true interstellar comet discovered. Here, we present results from observational programs at two Indian observatories, 2 m Himalayan Chandra Telescope Astronomical Observatory, Hanle (HCT) and 1.2 telescope Mount Abu Infrared Observatory (MIRO). Two epochs of imaging spectroscopy were carried out HCT three MIRO. We found CN to be dominant molecular emission on both epochs, 2019 November 30 December 22, distances rH = 2.013 2.031 au, respectively. The was inferred relatively depleted in Carbon bearing molecules basis low C2 C3 abundances. find production rate ratio, Q(C2)/Q(CN) 0.54 ± 0.18, pre-perihelion 0.34 0.12 post-perihelion. This classifies as being moderately carbon chain molecules. Using spectroscopic observations, believe have a chemically heterogeneous surface having variation abundance From infer dust-to-gas ratio similar comets Solar system. also compute nucleus size range 0.18 km ≤ r 3.1 km. Our observations show that 2I/Borisov’s behaviour analogous system comets.