Kruger 60 as a home system for 2I/Borisov -- a case study

Abstract

For the second discovered interstellar comet 2I/Borisov we searched for a candidate for its home system. We will never be sure which star or stellar system does this comet come from but obtaining a very small relative velocity and a promisingly small miss-distance, when tracing the motion of 2I/Borisov back in time in its movement through the space, makes an encountered body a good candidate for a source of this comet. In our long-standing project on studying Oort spike comets dynamics, we recently updated a list of potential stellar perturbers of cometary motion. This list was checked against a past, close and slow encounter with 2I/Borisov. Only one object from among 647 stars or stellar systems in our list, a double star Kruger 60, appeared as a potential candidate for the origin of this comet. However, a detailed analysis of this system's radial velocity uncertainty influence on our result showed, that the probability that Kruger 60 is a home system of 2I/Borisov is small. Finally, the usage of a new, unpublished systemic radial velocity of Kruger 60 system practically ruled out this possibility.