Searching for Possible Siblings of the Sun from a Common Cluster based on Stellar Space Velocities

TL;DR

This study develops a kinematic method to identify stars that may have originated from the same cluster as the Sun by analyzing their space velocities and past orbital encounters.

Contribution

It introduces a new approach combining velocity proximity and orbital encounter analysis to find potential solar siblings in the Hipparcos catalog.

Findings

Two candidate stars show close orbital encounters with the Sun.

Candidates have similar evolutionary status and metallicity as the Sun.

Method effectively identifies stars with shared origins based on kinematic data.

Abstract

We propose a kinematic approach to searching for the stars that could be formed with the Sun in a common "parent" open cluster. The approach consists in preselecting suitable candidates by the closeness of their space velocities to the solar velocity and analyzing the parameters of their encounters with the solar orbit in the past in a time interval comparable to the lifetime of stars. We consider stars from the Hipparcos catalog with available radial velocities. The Galactic orbits of stars have been constructed in the Allen--Santillan potential by taking into account the perturbations from the spiral density wave. We show that two stars, HIP 87382 and HIP 47399, are of considerable interest in our problem. Their orbits oscillate near the solar orbit with an amplitude of about 250 pc; there are short-term close encounters to distances <10 pc. Both stars have an evolutionary status and metallicity similar to the solar ones.