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Title: Discovery of Two New Hypervelocity Stars from the LAMOST Spectroscopic Surveys

Abstract

We report the discovery of two new unbound hypervelocity stars (HVSs) from the LAMOST spectroscopic surveys. They are, respectively, a B2V-type star of ∼7 M {sub ⊙} with a Galactic rest-frame radial velocity of 502 km s{sup −1} at a Galactocentric radius of ∼21 kpc and a B7V-type star of ∼4 M {sub ⊙} with a Galactic rest-frame radial velocity of 408 km s{sup −1} at a Galactocentric radius of ∼30 kpc. The origins of the two HVSs are not clear given their currently poorly measured proper motions. However, the future data releases of Gaia should provide proper motion measurements accurate enough to solve this problem. The ongoing LAMOST spectroscopic surveys are expected to yield more HVSs to form a statistical sample, providing vital constraints on understanding the nature of HVSs and their ejection mechanisms.

Authors:
; ;  [1]; ; ;  [2]; ;  [3];  [4];  [5]
  1. South-Western Institute for Astronomy Research, Yunnan University, Kunming 650500 (China)
  2. Department of Astronomy, Peking University, Beijing 100871 (China)
  3. Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)
  4. Department of Astronomy, Beijing Normal University, Beijing 100875 (China)
  5. Key Laboratory for the Structure and Evolution of Celestial Objects, Yunnan Observatories, CAS, Kunming 650216 (China)
Publication Date:
OSTI Identifier:
22654382
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 847; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; GALAXIES; LIMITING VALUES; PROPER MOTION; RADIAL VELOCITY; STARS

Citation Formats

Huang, Y., Liu, X.-W., Chen, B.-Q., Zhang, H.-W., Wang, C., Tian, Z.-J., Xiang, M.-S., Li, Y.-B., Yuan, H.-B., and Wang, B., E-mail: yanghuang@pku.edu.cn, E-mail: x.liu@pku.edu.cn, E-mail: zhanghw@pku.edu.cn. Discovery of Two New Hypervelocity Stars from the LAMOST Spectroscopic Surveys. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA894B.
Huang, Y., Liu, X.-W., Chen, B.-Q., Zhang, H.-W., Wang, C., Tian, Z.-J., Xiang, M.-S., Li, Y.-B., Yuan, H.-B., & Wang, B., E-mail: yanghuang@pku.edu.cn, E-mail: x.liu@pku.edu.cn, E-mail: zhanghw@pku.edu.cn. Discovery of Two New Hypervelocity Stars from the LAMOST Spectroscopic Surveys. United States. doi:10.3847/2041-8213/AA894B.
Huang, Y., Liu, X.-W., Chen, B.-Q., Zhang, H.-W., Wang, C., Tian, Z.-J., Xiang, M.-S., Li, Y.-B., Yuan, H.-B., and Wang, B., E-mail: yanghuang@pku.edu.cn, E-mail: x.liu@pku.edu.cn, E-mail: zhanghw@pku.edu.cn. Wed . "Discovery of Two New Hypervelocity Stars from the LAMOST Spectroscopic Surveys". United States. doi:10.3847/2041-8213/AA894B.
@article{osti_22654382,
title = {Discovery of Two New Hypervelocity Stars from the LAMOST Spectroscopic Surveys},
author = {Huang, Y. and Liu, X.-W. and Chen, B.-Q. and Zhang, H.-W. and Wang, C. and Tian, Z.-J. and Xiang, M.-S. and Li, Y.-B. and Yuan, H.-B. and Wang, B., E-mail: yanghuang@pku.edu.cn, E-mail: x.liu@pku.edu.cn, E-mail: zhanghw@pku.edu.cn},
abstractNote = {We report the discovery of two new unbound hypervelocity stars (HVSs) from the LAMOST spectroscopic surveys. They are, respectively, a B2V-type star of ∼7 M {sub ⊙} with a Galactic rest-frame radial velocity of 502 km s{sup −1} at a Galactocentric radius of ∼21 kpc and a B7V-type star of ∼4 M {sub ⊙} with a Galactic rest-frame radial velocity of 408 km s{sup −1} at a Galactocentric radius of ∼30 kpc. The origins of the two HVSs are not clear given their currently poorly measured proper motions. However, the future data releases of Gaia should provide proper motion measurements accurate enough to solve this problem. The ongoing LAMOST spectroscopic surveys are expected to yield more HVSs to form a statistical sample, providing vital constraints on understanding the nature of HVSs and their ejection mechanisms.},
doi = {10.3847/2041-8213/AA894B},
journal = {Astrophysical Journal Letters},
number = 1,
volume = 847,
place = {United States},
year = {Wed Sep 20 00:00:00 EDT 2017},
month = {Wed Sep 20 00:00:00 EDT 2017}
}