J/ApJ/868/70 Hot subdwarf stars from Gaia DR2 and LAMOST DR5 (Lei+, 2018)
New hot subdwarf stars identified in Gaia DR2 with LAMOST DR5 spectra.
Lei Z., Zhao J., Nemeth P., Zhao G.
<Astrophys. J., 868, 70 (2018)>
=2018ApJ...868...70L 2018ApJ...868...70L
ADC_Keywords: Stars, subdwarf; Cross identifications; Abundances;
Radial velocities; Photometry, G band; Spectral types
Keywords: Hertzsprung-Russell and C-M diagrams ; subdwarfs ; surveys
Abstract:
We selected 4593 hot subdwarf candidates from the Gaia DR2
Hertzsprung-Russell (HR) diagram. By combining the sample with Large
Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) DR5, we
identified 294 hot subdwarf stars, including 169 sdB, 63 sdOB,
31 He-sdOB, 22 sdO, 7 He-sdO, and 2 He-sdB stars. The atmospheric
parameters (e.g., Teff, logg, log(nHe/nH)) are obtained by fitting
the hydrogen (H) and helium (He) line profiles with synthetic spectra.
Two distinct He sequences of hot subdwarf stars are clearly presented
in the Teff-logg diagram. We found that the He-rich sequence consists
of the bulk of sdB and sdOB stars, as well as all of the He-sdB,
He-sdO, and He-sdOB stars in our samples, while all the stars in the
He-weak sequence belong to the sdO spectral type, combined with a few
sdB and sdOB stars. We demonstrated that the combination of Gaia DR2
and LAMOST DR5 allows one to uncover a huge number of new hot subdwarf
stars in our Galaxy.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 116 294 The information of 294 hot subdwarf stars identified
in this study
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See also:
II/207 : Palomar-Green catalog UV-excess stellar objects (Green+ 1986)
VI/65 : Evolutionary models of evolved stars (Dorman+ 1993)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
V/153 : LAMOST DR4 catalogs (Luo+, 2018)
J/A+A/400/939 : Stellar parameters of 115 HQS sdB stars (Edelmann+, 2003)
J/MNRAS/380/1098 : UV-upturn of elliptical galaxies model (Han+, 2007)
J/A+A/530/A28 : Priority targets for the MUCHFUSS project (Geier+, 2011)
J/MNRAS/427/2180 : GALEX survey subdwarf atmospheric parameters (Nemeth+, 2012)
J/ApJ/764/25 : FUSE spectra analysis of hot subdwarf stars (Jenkins, 2013)
J/ApJ/818/202 : Hot subdwarf stars in LAMOST DR1 (Luo+, 2016)
J/other/RAA/16.G7 : Nearby M subdwarfs from LAMOST DR2 (Bai+, 2016)
J/A+A/600/A50 : Catalog of hot subdwarf stars (Geier+, 2017)
J/A+A/616/A10 : Open clusters GaiaDR2 HR diagrams (Gaia Collaboration, 2018)
J/A+A/621/A38 : Gaia catalogue of hot subluminous stars (Geier+, 2019)
J/ApJS/240/31 : M-subdwarf research. I. LAMOST DR4 spectra (Zhang+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 F10.6 deg RAdeg LAMOST Right Ascension (J2000)
12- 20 F9.6 deg DEdeg LAMOST Declination (J2000)
22- 30 I9 --- LAMOST [2604051/584512022] LAMOST DR5 identifier
32 A1 --- Flag1 [*] *: also in Geier+ 2017, J/A+A/600/A50
33 A1 --- Flag2 d: also in Nemeth+ 2012, J/MNRAS/427/2180
34 A1 --- Flag3 D: also in Luo+ 2016, J/ApJ/818/202
36- 54 I19 --- Gaia Gaia DR2 (I/345) identifier
56- 60 I5 K Teff [21290/84550] Effective temperature (1)
62- 66 I5 K e_Teff [10/14680] Uncertainty in Teff
68- 71 F4.2 [cm.s2] log(g) [5/6.8] log surface gravity (1)
73- 76 F4.2 [cm.s2] e_log(g) [0/0.9] Uncertainty in log(g)
78 A1 --- l_log(He/H) Limit flag on log(He/H)
79- 83 F5.2 [-] log(He/H) [-3.5/4.1] log He/H number abundance (1)
85- 88 F4.2 [-] e_log(He/H) [0.01/1.1]? Uncertainty in log(He/H)
90- 95 F6.1 km/s RVel [-268.2/407.3] Radial velocity (1)
97-102 F6.2 mag Gmag [10.1/257.1] Apparent Gaia G band magnitude
104-108 F5.2 --- SNRU [10.4/16.5] Signal-to-Noise for u band image
110-116 A7 --- SClass Spectral classification type (2)
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Note (1): From the XTGrid fits.
Note (2): Spectral classification as follows:
He-sdB = 2 occurrences
He-sdO = 7 occurrences
He-sdOB = 31 occurrences
sdB = 169 occurrences
sdO = 22 occurrences
sd = 63 occurrences
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-Oct-2019