The Catalog of early-type Runaway stars from LAMOST-DR8

TL;DR

This study identifies 229 candidate runaway OB-type stars from the LAMOST-DR8 survey using combined spectroscopic and astrometric data, revealing their distribution mainly within the Galactic thin disk and uncovering binary candidates.

Contribution

It presents the first large-scale catalog of early-type runaway stars from LAMOST-DR8, combining radial velocities and Gaia data to identify candidates and analyze their properties.

Findings

229 runaway star candidates identified

Most candidates are within the Galactic thin disk

Two binary candidates with orbital periods of 40 and 61 days

Abstract

Runaway stars are OB-type stars ejected from their birthplace with large peculiar velocities. The leading hypothesis addressed in their formation includes the supernova ejection mechanism and the dynamic ejection scenario. Identification of runaway populations is the first step to investigating their formation and evolution. Here we present our work of searching for Galactic runaway candidate stars from the LAMOST Medium-Resolution Survey DR8 database. After studying the kinematic properties for a collection of 4,432 early-type stars, predominantly B-type stars, using the radial velocity measurements from LAMOST DR8 and astrometric solutions made by Gaia DR3, we identified 229 runaway candidate stars. They span a wide distribution in projected rotational velocities. We investigated the Galactic spatial distribution of the runaway population and noticed that most of them likely reside within the Galactic thin disk. Based upon analyzing the Doppler shifts of the candidate stars, we found two binary runaway candidates displaying velocity variation with estimated orbital periods of 40 and 61 days.