Unusual polarimetric properties for interstellar comet 2I/Borisov

• DOI: 10.1038/s41467-021-22000-x
• Publication Date: 2021-03-30T16:02:59Z
• Authors: S. Bagnulo; A. Cellino; L. Kolokolova; R. Nežič; T. Santana-Ros; G. Borisov; A. A. Christou; Ph. Bendjoya; M. Devogèle
• Keywords: Interstellar comet; Coma (optics); Jupiter (rocket family)

So far, only two interstellar objects have been observed within our Solar System. While the first one, 1I/'Oumuamua, had asteroidal characteristics, second 2I/Borisov, showed clear evidence of cometary activity. We performed polarimetric observations comet 2I/Borisov using European Southern Observatory Very Large Telescope to derive physical characteristics its coma dust particles. Here we show that polarization is higher than what typically measured for System comets. This feature distinguishes from dynamically evolved such as Jupiter-family and all short- long-period comets in The object with similar properties C/1995 O1 (Hale-Bopp), an believed approached Sun once before apparition 1997. Unlike Hale-Bopp many other comets, though, shows a polarimetrically homogeneous coma, suggesting it even more pristine object.