# HIP 21539 is not a past very close neighbour of the Sun

## TL;DR

This study corrects previous claims by using new data to show that HIP 21539 did not pass close to the Sun, instead remaining far away and not affecting the Oort cloud.

## Contribution

It provides a revised trajectory for HIP 21539 using updated radial velocity and Gaia data, disproving earlier close approach estimates.

## Key findings

- Closest approach is now 17 pc, not 1.9 pc.
- HIP 21539 did not perturb the Oort cloud.
- Previous close approach estimate was incorrect.

## Abstract

Aims: A previous study claimed that the star HIP 21539 passed close to the Sun, at a distance of 1.9 pc, around 0.14 Myr ago. We show that this is not the case. Methods: We redetermined the trajectory of the star relative to the Sun using a new accurate radial velocity from the HARPS spectrograph combined with the recent Gaia-TGAS astrometry. Results: With this new data, the closest approach of HIP 21539 to the Sun is now 17 pc, instead of 1.9 pc. Conclusions: At this distance, the star has not perturbed the Oort cloud.