Hot subdwarf stars identified in LAMOST DR8 with single-lined and composite spectra by Zhenxin Lei et al. on Wednesday 23 November

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. 15 composite sdB stars

fall in the high probability binary region of 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-spectra sample. But we could not come to a conclusion whether this

feature is connected to the formation history of hot subdwarf stars before

their binary natures are confirmed.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.12323v1