J/ApJ/889/117 Hot subdwarf stars from Gaia DR2 & LAMOST DR6+7. I. (Lei+, 2020)
Hot subdwarf stars identified in Gaia DR2 with spectra of LAMOST DR6 and DR7.
I. Single-lined spectra.
Lei Z., Zhao J., Nemeth P., Zhao G.
<Astrophys. J., 889, 117-117 (2020)>
=2020ApJ...889..117L 2020ApJ...889..117L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, subdwarf; Abundances; Spectral types
Keywords: Subdwarf stars; Stellar classification; Surveys
Abstract:
182 single-lined hot subdwarf stars are identified by using spectra
from the sixth and seventh data releases (DR6 and DR7) of the Large
Sky Area Multi-Object Fibre Spectroscopic Telescope survey. We
classified all the hot subdwarf stars using a canonical classification
scheme, and got 89 sdB, 37 sdOB, 26 sdO, 24 He-sdOB, 3 He-sdO, and 3
He-sdB stars, respectively. Among these stars, 108 hot subdwarfs are
newly discovered, while 74 stars were reported by previous catalogs.
The atmospheric parameters of these stars were obtained by fitting the
hydrogen (H) and helium (He) lines with non-local thermodynamic
equilibrium model atmospheres. The atmospheric parameters confirm the
two He sequences and the two subgroups of He-sdOB stars in our
samples, which were found by previous studies in the
Teff-log(nHe/nH) diagram. Our results demonstrate different origins
of field hot subdwarf stars and extreme horizontal branch stars in
globular clusters, and provide strict observational limits on the
formation and evolution models of the different sub-types of these
evolved objects. Based on the results, we evaluated the completeness
of the Geier+ (2017, J/A+A/600/A50) catalog. We found the fraction of
hot subwarf stars is between 10% and 60%, depending on the brightness
of the sample. A more accurate estimation for the hot subdwarf
fraction can be obtained when similar results from composite spectra
will become available.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 107 182 Information on the 182 hot subdwarf stars
identified in this study
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See also:
III/137 : Spectroscopically Identified Hot Subdwarf Stars (Kilkenny+ 1988)
VI/65 : Evolutionary models of evolved stars (Dorman+ 1993)
III/258 : Revised and updated First Byurakan Survey (FBS) (Mickaelian, 2008)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
V/164 : LAMOST DR5 catalogs (Luo+, 2019)
J/ApJ/419/596 : Pop I UV radiation models (Dorman+, 1993)
J/MNRAS/287/867 : Edinburgh-Cape Blue Object Survey. Zone 1. (Kilkenny+ 1997)
J/A+A/400/939 : Stellar parameters of 115 HQS sdB stars (Edelmann+, 2003)
J/MNRAS/427/2180 : GALEX survey subdwarf atmospheric parameters (Nemeth+, 2012)
J/A+A/565/A100 : NGC 288 hot horizontal branch stars abund. (Moehler+, 2014)
J/MNRAS/446/4078 : New white dwarf stars in SDSS DR10 (Kepler+, 2015)
J/A+A/576/A44 : Hot subdwarf binaries from MUCHFUSS (Kupfer+, 2015)
J/ApJ/818/202 : Hot subdwarf stars in LAMOST DR1 (Luo+, 2016)
J/MNRAS/455/3413 : New WD and subdwarf stars in SDSS DR12 (Kepler+, 2016)
J/A+A/600/A50 : Catalog of hot subdwarf stars (Geier+, 2017)
J/A+A/618/A15 : Parameters of EHB stars in ω Cen (Latour+, 2018)
J/ApJ/868/70 : Hot subdwarf stars from Gaia DR2 and LAMOST DR5 (Lei+, 2018)
J/A+A/621/A38 : Gaia catalogue of hot subluminous stars (Geier+, 2019)
J/ApJ/881/135 : Hot subdwarf stars from Gaia2 & LAMOST DR5. II. (Lei+, 2019)
http://www.lamost.org/ : LAMOST home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 F11.7 deg RAdeg LAMOST right ascension (J2000)
13- 13 A1 --- G17 [*] *: source also in
Geier+ 2017, J/A+A/600/A50
15- 24 F10.7 deg DEdeg LAMOST declination (J2000)
26- 34 I9 --- ObsID LAMOST observation identifier
36- 54 I19 --- Gaia Gaia DR2 source identifier
56- 60 I5 K Teff [22230/79240] Effective temperature (1)
62- 66 I5 K e_Teff [10/11150] Uncertainty in Teff
68- 71 F4.2 [cm/s2] log(g) [5/6.9] Log surface gravity (1)
73- 76 F4.2 [cm/s2] e_log(g) [0/0.8] Uncertainty in log(g)
78- 78 A1 --- l_logHe/H Upper limit flag on logHe/H
80- 84 F5.2 [-] logHe/H [-3.5/3] Log He/H abundance (1)
86- 89 F4.2 [-] e_logHe/H [0.01/1.1]? Uncertainty in logHe/H
91- 93 I3 --- SNRu [10/162] Signal to noise in the u band
95- 99 F5.2 mag Gmag [12/18] Apparent Gaia DR2 G band magnitude
101-107 A7 --- SpT Spectral classification
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Note (1): As in Lei+ (2018, J/ApJ/868/70 and 2019, J/ApJ/881/135), we employed
the spectral analysis tool, XTgrid (Nemeth+ 2012, J/MNRAS/427/2180 and
2014ASPC..481...95N 2014ASPC..481...95N) to analyze the selected 607 LAMOST DR6 & DR7 spectra.
See Section 3.
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History:
From electronic version of the journal
References:
Lei et al. Paper I. 2020ApJ...889..117L 2020ApJ...889..117L This Catalog
Luo et al. Paper II. 2020ApJ...898...64L 2020ApJ...898...64L
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 13-Jul-2021