Discovery of Two New Hypervelocity Stars from the LAMOST Spectroscopic Surveys
- South-Western Institute for Astronomy Research, Yunnan University, Kunming 650500 (China)
- Department of Astronomy, Peking University, Beijing 100871 (China)
- Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)
- Department of Astronomy, Beijing Normal University, Beijing 100875 (China)
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.
- OSTI ID:
- 22654382
- Journal Information:
- Astrophysical Journal Letters, Vol. 847, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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