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arXiv · 2402.12428

Pre-perihelion Monitoring of Interstellar Comet 2I/Borisov

George P. Prodan·Marcel Popescu·Javier Licandro·Mohammad Akhlaghi·Julia de León·Eri Tatsumi·Bogdan Adrian Pastrav·Jacob M. Hibbert·Ovidiu Văduvescu·Nicolae Gabriel Simion·Enric Pallé·Norio Narita·Akihiko Fukui·Felipe Murgas
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Abstract

The discovery of interstellar comet 2I/Borisov offered the unique opportunity to obtain a detailed analysis of an object coming from another planetary system, and leaving behind material in our interplanetary space. We continuously observed 2I/Borisov between October 3 and December 13, 2019 using the 1.52-m Telescopio Carlos Sánchez equipped with MuSCAT2 instrument, and the 2.54-m Isaac Newton Telescope with Wide Field Camera. We characterize its morphology and spectro-photometric features using the data gathered during this extended campaign. Simultaneous imaging in four bands ($g$, $r$, $i$, and $z_s$) reveals a homogeneous composition and a reddish hue, resembling Solar System comets, and as well a diffuse profile exhibiting familiar cometary traits. We discern a stationary trend fluctuating around a constant activity level throughout October and November 2019. Subsequently, a reduction in activity is observed in December. Dust production and mass loss calculations indicate approximately an average of 4 kg/s before perihelion, while after perihelion the net mass loss is about 0.6 kg/s. Our simulations indicate the most probable size of coma dust particles should be in the range 200-250 nm, and the terminal speed around 300 m/s. The spectrum acquired with the 4.2-m William Herschel Telescope shows the presence of a strong CN line for which we find a gas production rate of $1.2 \times 10^{24}~s^{-1}$. We also detected NH$_2$ and OI bands. The ratio between NH$_2$ and CN productions is $\log (NH_2/CN) =-0.2$. Overall, this observing campaign provides a new understanding of 2I/Borisov's unique characteristics and activity patterns.

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George P. Prodan, Marcel Popescu, Javier Licandro, Mohammad Akhlaghi, Julia de León, Eri Tatsumi, Bogdan Adrian Pastrav, Jacob M. Hibbert, Ovidiu Văduvescu, Nicolae Gabriel Simion, Enric Pallé, Norio Narita, Akihiko Fukui, Felipe Murgas. 2024-02-19. Pre-perihelion Monitoring of Interstellar Comet 2I/Borisov. https://doi.org/10.1093/mnras%2Fstae539

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