Approach of the Hyades star cluster to the Solar system

Abstract

ABSTRACT We present the results of calculations of the motion of the Hyades open cluster in the gravitational field of the Galaxy in the recent past. Our calculations show that the recent close passage of Hyades by the Solar system could cause a noticeable shift of the perihelion distances q of comets. The shift is negligible from q = 3 au to 2.6 au for the semimajor axes a = 14 210 au, but for a = 40 000 au, the perihelion could change from q = 35 au to 34 au, and much more for distant orbits. This could result in the detection of new comets, and drive the migration of comets from the outer region of the Solar system towards the orbit of Neptune. The effect can be enhanced by the simultaneous passage of several stars. For example, if several stars approached the Sun simultaneously in the time interval from −1.5 to −1.0 Myr, the effect may be amplified up to ten times.