Search for Kinematic Siblings of the Sun Based on Data from the XHIP Catalog

TL;DR

This study identifies potential solar siblings by analyzing the past Galactic orbits of 1872 stars from the XHIP catalog, revealing three new candidates and confirming previous ones, with HIP 87382 being the most promising.

Contribution

It introduces a method to trace stars' Galactic orbits over 4.5 Gyr considering spiral density wave perturbations, identifying new potential solar siblings.

Findings

Three new stars with orbits close to the Sun's in the past.

HIP 87382 is the most likely solar sibling candidate.

Confirmed previous candidates HIP 47399 and HIP 87382.

Abstract

From the XHIP catalogue, we have selected 1872 F-G-K stars with relative parallax measurement errors <20% and absolute values of their space velocities relative to the Sun <15 km/s. For all these stars, we have constructed their Galactic orbits for 4.5 Gyr into the past using an axisymmetric Galactic potential model with allowance made for the perturbations from the spiral density wave. Parameters of the encounter with the solar orbit have been calculated for each orbit. We have detected three new stars whose Galactic orbits were close to the solar one during a long time interval in the past. These stars are HIP 43852, HIP 104047, and HIP 112158. The spectroscopic binary HIP 112158 is poorly suited for the role of a kinematic sibling of the Sun by its age and spectroscopic characteristics. For the single star HIP 43852 and the multiple system HIP 104047, this role is quite possible. We have also confirmed the status of our previously found candidates for close encounters, HIP 47399 and HIP 87382. The star HIP 87382 with a chemical composition very close to the solar one is currently the most likely candidate, because it persistently shows close encounters with the Sun on time scales of more than 3 Gyr when using various Galactic potential models both without and with allowance made for the influence of the spiral density wave.