Hot subdwarf stars from Gaia with LAMOST sp. II. RVs

DOI

Combining LAMOST radial velocities with Gaia parallaxes and proper motions, we present 3D Galactic space motions and the orbits of 182 single-lined hot subdwarf stars. These stars were identified by Lei+ (Paper I; 2020, J/ApJ/889/117) in Gaia DR2 with LAMOST DR6 and DR7 spectra. He-rich hot subdwarf stars with log(y)>=0 show the largest standard deviations of the Galactic velocity components and orbital parameters, while those with -1<=log(y)<=0 exhibit the second largest standard deviations. The two groups of He-deficient stars with log(y){<}-1 show similar standard deviations, which are systematically lower compared to He-rich stars. We also present a kinematic population classification of the four hot subdwarf helium groups based on their positions in the U-V velocity diagram, the J_Z_- eccentricity diagram, and their Galactic orbits. The overall tendency of the fractional distributions of the four hot subdwarf helium groups in the halo, thin disk, and thick disk is largely consistent with the findings reported by Luo+ (2019ApJ...881....7L) based on LAMOST DR5, which appears to support predictions of binary population synthesis. He-deficient stars with -2.2<=log(y){<}-1 likely originate from a stable Roche lobe overflow channel, He-deficient stars with log(y){=0 from the merger channel of double He white dwarf stars. The fraction of He-rich hot subdwarf stars with -1<=log(y)<0 in the thin disk and the halo is far higher than that in the thick disk, which implies that these stars have different formation channels in the thin disk and in the halo.

Cone search capability for table J/ApJ/898/64/table1 (Atmospheric parameters, space positions, orbital parameters and galactic velocities for 182 single-lined hot subdwarf stars observed in Gaia DR2 and LAMOST DR6 and DR7)

Identifier
DOI http://doi.org/10.26093/cds/vizier.18980064
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/ApJ/898/64
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/898/64
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/898/64
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/ApJ/898/64
Provenance
Creator Luo Y.; Nemeth P.; Li Q.
Publisher CDS
Publication Year 2021
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Exoplanet Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy