A catalogue of young runaway Hipparcos stars within 3kpc from the Sun

TL;DR

This study identifies and catalogs approximately 2,547 young runaway stars within 3 kpc of the Sun using Hipparcos data, extending the definition of runaway stars beyond traditional spectral types and velocities.

Contribution

It provides a new, comprehensive catalogue of young runaway stars of various spectral types, applying diverse selection criteria and evolutionary models to identify candidates.

Findings

Approximately 27% of young stars are runaway candidates.

Catalog includes 2,547 runaway star candidates with less than 20% contamination.

Methodology extends runaway star identification to all spectral types and ages up to 50 Myr.

Abstract

Traditionally runaway stars are O and B type stars with large peculiar velocities.We want to extend this definition to young stars (up to ~50 Myr) of any spectral type and identify those present in the Hipparcos catalogue applying different selection criteria such as peculiar space velocities or peculiar one-dimensional velocities. Runaway stars are important to study the evolution of multiple star systems or star clusters as well as to identify origins of neutron stars. We compile distances, proper motions, spectral types, luminosity classes, V magnitudes and B-V colours and utilise evolutionary models from different authors to obtain star ages and study a sample of 7663 young Hipparcos stars within 3 kpc from the Sun. Radial velocities are obtained from the literature. We investigate the distributions of the peculiar spatial velocity, the peculiar radial velocity as well as the peculiar tangential velocity and its one-dimensional components and obtain runaway star probabilities for each star in the sample. In addition, we look for stars that are situated outside any OB association or OB cluster and the Galactic plane as well as stars of which the velocity vector points away from the median velocity vector of neighbouring stars or the surrounding local OB association/ cluster although the absolute velocity might be small. We find a total of 2547 runaway star candidates (with a contamination of normal Population I stars of 20 per cent at most). Thus, after subtraction of those 20 per cent, the runaway frequency among young stars is about 27 per cent. We compile a catalogue of runaway stars which will be available via VizieR.