Probabilities for Solar Siblings

TL;DR

This study assesses the likelihood of identifying Solar Siblings—stars born in the same cluster as the Sun—by analyzing orbital models and extends the sample of potential candidates, estimating that up to 10% of original cluster members may still be nearby.

Contribution

It evaluates the sensitivity of Solar Sibling identification to Galactic models and expands the orbital sample to refine membership probability estimates.

Findings

Up to 10% of Solar Siblings may still be within 100 pc of the Sun.

Membership probabilities are generally low due to long orbital evolution.

The study highlights the importance of Galactic model parameters in identifying Solar Siblings.

Abstract

We have shown previously (Bobylev et al 2011) that some of the stars in the Solar neighborhood today may have originated in the same star cluster as the Sun, and could thus be called Solar Siblings. In this work we investigate the sensitivity of this result to Galactic models and to parameters of these models, and also extend the sample of orbits. There are a number of good candidates for the Sibling category, but due to the long period of orbit evolution since the break-up of the birth cluster of the Sun, one can only attach probabilities of membership. We find that up to 10% (but more likely around 1 %) of the members of the Sun's birth cluster could be still found within 100 pc from the Sun today.