A new Hyper-Runaway star discovered from LAMOST and GAIA: ejected almost in the galactic rotation direction
Abstract
In this paper, we report the discovery of a new late-B type unbound hyper-runaway star (LAMOST-HVS4) from the LAMOST spectroscopic surveys. According to its atmospheric parameters, it is either a B-type main sequence (MS) star or a blue horizontal branch (BHB) star. Its Galactocentric distance and velocity are 30.3 +/- 1.6 kpc and 586 +/- 7 km/s if it is an MS star, and they are 13.2 +/- 3.7 kpc and 590 +/- 7 km/s if a BHB star. We track its trajectories back, and find that the trajectories intersect with the Galactic disk and the Galactic center lies outside of the intersection region at the 3 sigma confidence level. We investigate a number of mechanisms that could be responsible for the ejection of the star, and find that it is probably ejected from the Galactic disk by supernova explosion or multiple-body interactions in dense young stellar clusters.
Keywords
Cite
@article{arxiv.1807.00167,
title = {A new Hyper-Runaway star discovered from LAMOST and GAIA: ejected almost in the galactic rotation direction},
author = {Yin-Bi Li and A-Li Luo and Gang Zhao and You-Jun Lu and Xue-Sen Zhang and Fu-Peng Zhang and Bing Du and Fang Zuo and Lan Zhang and Yang Huang and Mao-Sheng Xiang and Jing-Kun Zhao and Yong-Heng Zhao and Zhan-Wen Hna},
journal= {arXiv preprint arXiv:1807.00167},
year = {2018}
}
Comments
7 pages, 3 figures, accepted by AJ