Hot Subdwarf Stars Identified in LAMOST DR8 with Single-lined and Composite Spectra

0569295 - ASÚ 2024 RIV GB eng J - Journal Article
Lei, Z. - He, R. - Németh, Péter - Vos, Joris - Zou, X. - Hu, K. - Xiao, H. - Yan, H. - Zhao, J.
Hot Subdwarf Stars Identified in LAMOST DR8 with Single-lined and Composite Spectra.
Astrophysical Journal. Roč. 942, č. 2 (2023), č. článku 109. ISSN 0004-637X. E-ISSN 1538-4357
R&D Projects: GA ČR(CZ) GA22-34467S
Institutional support: RVO:67985815
Keywords : B subdwarf stars * wide binary stars * solar and stellar astrophysics
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 4.9, year: 2022
Method of publishing: Open access

A total of 222 hot subdwarf stars were identified with LAMOST DR8 spectra, among which 131 stars show composite spectra and have been decomposed, while 91 stars present single-lined spectra. Atmospheric parameters of all sample stars were obtained by fitting hydrogen (H) and helium (He) line profiles with synthetic spectra. Two long-period composite sdB binaries were newly discovered by combining our sample with the non-single-star data from Gaia DR3. One of the new systems presents the highest eccentricity (i.e., 0.5 +/- 0.09) among known wide sdB binaries, which is beyond model predictions. A total of 15 composite sdB stars fall in the high-probability binary region of the RUWE-AEN plane and deserve priority follow-up observations to further study their binary nature. A distinct gap is clearly presented among temperatures of cool companions for our composite-spectrum sample, but we could not come to a conclusion as to whether this feature is connected to the formation history of hot subdwarf stars before their binary natures are confirmed.
Permanent Link: https://hdl.handle.net/11104/0341994