J/ApJS/256/28 Hot subdwarf stars with Gaia DR2 and LAMOST DR7 data (Luo+, 2021)
Hot subdwarf atmospheric parameters, kinematics, and origins based on 1587 hot
subdwarf stars observed in Gaia DR2 and LAMOST DR7.
Luo Y., Nemeth P., Wang K., Wang X., Han Z.
<Astrophys. J. Suppl. Ser., 256, 28-28 (2021)>
=2021ApJS..256...28L 2021ApJS..256...28L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, subdwarf; Abundances; Proper motions; Radial velocities;
Space velocities; Stars, diameters; Stars, halo; Optical
Keywords: O subdwarf stars; Stellar kinematics
Abstract:
Based on the Gaia DR2 catalog of hot subdwarf star candidates, we
identified 1587 hot subdwarf stars with spectra in LAMOST DR7. We
present atmospheric parameters for these stars by fitting the LAMOST
spectra with TLUSTY/SYNSPEC non-LTE synthetic spectra. Combining
LAMOST radial velocities and Gaia Early Data Release 3 (EDR3)
parallaxes and proper motions, we also present the Galactic space
positions, velocity vectors, orbital parameters and the Galactic
population memberships of the stars. With our He classification
scheme, we identify four groups of He rich hot subdwarf stars in the
Teff-logg and Teff-log(nHe/nH) diagrams. We find two extreme
He-rich groups (eHe-1 and eHe-2) for stars with log(nHe/nH)≥0 and two
intermediate He-rich groups (iHe-1 and iHe-2) for stars with
-1≤log(nHe/nH)<0. We also find that over half of the stars in Group
eHe-1 are thick-disk stars, while over half of the stars in Group
eHe-2 correspond to thin-disk stars. The disk population fractions of
Group iHe-1 are between those of Group eHe-1 and eHe-2. Almost all of
the stars in Group iHe-2 belong to the thin disk. These differences
indicate that the four groups probably have very different origins.
Comparisons between hot subdwarf stars in the halo and in the Galactic
globular cluster ω Cen show that only He-deficient stars with
-2.2≤log(nHe/nH)<-1 have similar fractions. Hot subdwarfs with
log(nHe/nH)≥0 in ω Cen have no counterparts in the thick-disk
and halo populations, but they appear in the thin disk.
Description:
By cross-matching the catalog of Geier+ (2019, J/A+A/621/A38) and
LAMOST DR7, and after rejecting bad spectra, MS stars, WDs, and objects
with strong CaII H&K, MgI, or CaII absorption lines, we obtained
1587 hot subdwarf stars with a spectral signal-to-noise (S/N) over 10
in the g-band.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 287 1587 Atmospheric parameters, space positions, orbital
parameters and galactic velocities for 1587 hot
subdwarf stars identified in Gaia DR2 with
spectra of LAMOST DR7
table2.dat 129 665 The excluded targets from the Gaia DR2 catalogue
of hot subdwarf star candidates with spectra
from LAMOST DR7
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See also:
VI/65 : Evolutionary models of evolved stars (Dorman+ 1993)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
V/164 : LAMOST DR5 catalogs (Luo+, 2019)
I/352 : Distances to 1.47 billion stars in Gaia EDR3 (Bailer-Jones+, 2021)
J/ApJ/419/596 : Pop I UV radiation models (Dorman+, 1993)
J/A+A/400/877 : White dwarfs 3D kinematics from SPY project (Pauli+, 2003)
J/A+A/400/939 : Stellar parameters of 115 HQS sdB stars (Edelmann+, 2003)
J/A+A/430/223 : Parameters of cool companions of sdB stars (Lisker+, 2005)
J/A+A/447/173 : 3D-kinematics of WDs from SPY project. II. (Pauli+, 2006)
J/MNRAS/380/1098 : UV-upturn of elliptical galaxies model (Han+, 2007)
J/MNRAS/427/2180 : GALEX survey subdwarf atmospheric parameters (Nemeth+, 2012)
J/A+A/551/A31 : Spectral classification for hot subdwarfs (Drilling+, 2013)
J/A+A/569/A15 : KIC 10553698A asteroseismology (Ostensen+, 2014)
J/A+A/576/A44 : Hot subdwarf binaries from MUCHFUSS (Kupfer+, 2015)
J/A+A/577/A26 : Radial velocities of hot subluminous stars (Geier+, 2015)
J/ApJ/818/202 : Hot subdwarf stars in LAMOST DR1 (Luo+, 2016)
J/AJ/156/18 : Binary companions of evolved stars (Price-Whelan+, 2018)
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 Gaia DR2 & LAMOST DR5 II. (Lei+, 2019)
J/A+A/630/A130 : Co-added spectra of HD127493 and HZ44 (Dorsch+, 2019)
J/ApJ/889/117 : Hot subdwarf stars from Gaia & LAMOST DR6+7. I. (Lei+, 2020)
J/A+A/635/A193 : Catalogue of hot subdwarf stars DR2 (Geier, 2020)
J/ApJ/898/64 : Hot subdwarf stars from Gaia with LAMOST sp. II. (Luo+, 2020)
J/A+A/642/A180 : Hot subdwarf stars binarity (Pelisoli+, 2020)
J/A+A/643/A22 : UVES spectra of Feige 46 and LSIV -14 116 (Dorsch+, 2020)
http://dr7.lamost.org/ : LAMOST DR7 home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- LAMOST LAMOST target (JHHMMSS.ss+DDMMSS.s)
21- 30 F10.6 deg RAdeg Barycentric Right Ascension (ICRS)
at epoch 2000.0
32- 40 F9.6 deg DEdeg Barycentric Declination (ICRS)
at epoch 2000.0
42- 46 I5 K Teff [18313/80000] Stellar effective temperature
48- 51 I4 K e_Teff [0/7763] Standard error in Teff
53- 56 F4.2 [cm/s2] logg [4.5/6.6] Stellar surface gravity
58- 61 F4.2 [cm/s2] e_logg [0/0.7] Standard error in logg
63- 67 F5.2 [Sun] log(y) [-4.3/2.5] Stellar surface He abundance
y=n(He)/n (H)
69- 72 F4.2 [Sun] e_log(y) [0/5.7] Standard error in log(y)
74- 80 F7.3 mas/yr pmRA [-95.6/82.1] Gaia EDR3 proper motion in RA
82- 86 F5.3 mas/yr e_pmRA [0.01/0.9] Standard error in pmRA
88- 94 F7.3 mas/yr pmDE [-97.5/65.3] Gaia EDR3 proper motion in DE
96- 100 F5.3 mas/yr e_pmDE [0.01/0.6] Standard error in pmDE
102- 106 I5 pc dist [116/16835] Gaia EDR3 stellar distance
108- 112 I5 pc e_dist [0/13806] Standard error in dist
114- 117 I4 km/s RVel [-391/406] Radial velocity from LAMOST DR7
spectra
119- 121 I3 km/s e_RVel [5/147] Standard error in RVel
123- 129 F7.3 kpc X [-18.4/4.5] Galactic position towards
Galactic center
131- 135 F5.3 kpc e_X [0/7] Standard error in X
137- 142 F6.3 kpc Y [-6.3/15.6] Galactic position along
Galactic rotation
144- 148 F5.3 kpc e_Y [0/6.1] Standard error in Y
150- 156 F7.3 kpc Z [-12.8/12.3] Galactic position towards
north Galactic pole
158- 162 F5.3 kpc e_Z [0/8.5] Standard error in Z
164- 167 I4 km/s U [-397/473] Galactic radial velocity
positive towards Galactic center
169- 171 I3 km/s e_U [0/257]? Standard error in U
173- 176 I4 km/s V [-457/479] Galactic rotational velocity
along Galactic rotation
178- 180 I3 km/s e_V [0/381] Standard error in V
182- 185 I4 km/s W [-284/318] Galactic velocity towards north
Galactic pole
187- 189 I3 km/s e_W [0/197] Standard error in W
191- 196 F6.2 kpc Rap [5.8/901] Apocenter radius (1)
198- 204 F7.2 kpc e_Rap [0/1396]? Standard error in Rap
206- 210 F5.2 kpc Rperi [0.01/17.06] Pericenter radius (1)
212- 216 F5.2 kpc e_Rperi [0/11] Standard error in Rperi
218- 223 F6.2 kpc Zmax [0.02/309] Maximum vertical height (1)
225- 230 F6.2 kpc e_Zmax [0/492] Standard error in Zmax
232- 235 F4.2 --- ecc [0/1] Eccentricity (1)
237- 240 F4.2 --- e_ecc [0/0.3] Standard error in ecc
242- 249 F8.2 kpc/km/s Jz [-4785/6294] Z-component of angular
momentum (1)
251- 257 F7.2 kpc/km/s e_Jz [0.25/5131] Standard error in Jz
259- 263 F5.2 --- zn [0/18] Normalised z-extent of the orbit (1)
265- 268 F4.2 --- e_zn [0/8] Standard error in zn
270 I1 --- Group [0/4] Group name for He-rich stars (2)
272- 273 A2 --- Pop Population classification (3)
275- 277 I3 % pTH Probability in thin disk
279- 281 I3 % pTK Probability in thick disk
283- 285 I3 % pH Probability in halo
287 A1 --- New New hot subdwarf star
(Y=Yes, 224 occurrences; N=No)
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Note (1): From the numerical orbit integration.
Note (2): Group as follows:
1 = eHe-1;
2 = eHe-2;
3 = iHe-1;
4 = iHe-2.
Note (3): Population classification as follows:
H = Halo (240 occurrences)
TK = thick disk (568 occurrences)
TH = thin disk (779 occurrences)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- LAMOST LAMOST target (JHHMMSS.ss+DDMMSS.s)
21- 39 I19 --- GaiaEDR3 Unique Gaia EDR3 source identifier
41- 50 F10.6 deg RAdeg Barycentric Right Ascension (ICRS)
52- 60 F9.6 deg DEdeg Barycentric Declination (ICRS)
62- 67 F6.3 mas Plx [-2.5/3.9]? Gaia EDR3 stellar parallax
69- 73 F5.3 mas e_Plx [0.01/0.7]? Standard error in Plx
75- 81 F7.3 mas/yr pmRA [-42/42.2]? Gaia EDR3 proper motion in RA
83- 87 F5.3 mas/yr e_pmRA [0.01/0.8]? Standard error in pmRA
89- 96 F8.3 mas/yr pmDE [-111.4/18]? Gaia EDR3 proper motion in DE
98-102 F5.3 mas/yr e_pmDE [0.01/0.6]? Standard error in pmDE
104-110 F7.4 mag Gmag [9.3/18.7]? Gaia EDR3 G-band magnitude
112-118 F7.4 mag BP-RP [-0.6/1.3]? Gaia EDR3 BP-RP color index
120-129 A10 --- spClass Spectra classification (1)
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Note (1): Spectral classes are as follows:
BHB = Blue Horizontal Branch star (27 occurrences)
CV = Cataclysmic Variable star (37 occurrences)
DA = white dwarfs with H lines only (35 occurrences)
DB = white dwarfs with neutral He lines only (5 occurrences)
MS-B = B type main sequence star (22 occurrences)
MS-A = A type main sequence star (86 occurrences)
sdA = A type subdwarf star (142 occurrences)
sd+MS = hot subdwarf - Main Sequence binary candidates (240 occurrences)
UNK = Bad spectra which we were unable to classify (41 occurrences)
Unreliable = Spectra with low signal (25 occurrences)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 28-Jan-2022