Important stellar perturbers found during the StePPeD database update based on Gaia EDR3 data

Abstract

Context. In 2020, the initial version of the Stellar Potential Perturbers Database (StePPeD) was presented with the aim to deliver up-to-date information on the stars and stellar systems that may perturb a long-period comet motion. We used the minimal distance between a star and the Sun as a selecting tool when compiling a list of interesting objects with close encounters with the Solar System, and our selection for that study was based on Gαiα DR2 data. Aims. When the Gaia EDR3 data release was published, it became necessary to update this database. Additionally, we performed Monte Carlo simulations to obtain uncertainties on the parameters of the closest approach to the Sun of each object. Methods. We recalculated the close approach parameters of all stars in the previous StePPeD release, which resulted in removing approximately one-third of the total. Then we searched for new candidates in the whole Gaia EDR3 catalogue. We also take into account the duplicity of the found stars and additionally searched for double stars passing near the Sun which had been overlooked in previous papers. We also found the necessary mass estimates for new objects and updated this information for previously selected stars. Results. After a careful checking of all the collected data, we composed a new list of 155 potential stellar perturbers of the long-period comet motion. We applied a new threshold of 2 pc for the minimum star-Sun distance. This list consists of 146 single stars and nine multiple systems. For each object, we also estimated the uncertainty of the parameters of their closest approach to the Sun. Among these stars, we found a new potential strong past perturber, HD 7977, and confirmed the plausibility of a similar action on the part of Gliese 710 in the future.