J/ApJS/271/21 He-rich hot subdwarf stars from LAMOST and Gaia DR3 (Luo+, 2024)
He-rich hot subdwarf stars observed in Gaia DR3 and LAMOST DR7: carbon and
nitrogen abundances and kinematics.
Luo Y., Nemeth P., Wang K., Pan Y.
<Astrophys. J. Suppl. Ser., 271, 21 (2024)>
=2024ApJS..271...21L 2024ApJS..271...21L
ADC_Keywords: Abundances; Stars, subdwarf; Rotational velocities;
Radial velocities; Space velocities; Stars, diameters;
Spectra, optical
Keywords: Subdwarf stars
Abstract:
We conducted an analysis of the abundances of He, C, and N in
210 He-rich hot subdwarfs observed within both the Gaia Data Release 3
(DR3) and LAMOST DR7 data sets. This analysis involved fitting the
LAMOST spectra with Tlusty/Synspec non-LTE synthetic spectra. By
examining the Galactic spatial positions, velocity vectors, and
orbital parameters of these stars, we determined their Galactic
population memberships utilizing LAMOST radial velocities and Gaia DR3
parallaxes along with proper motions. Our investigation revealed two
positive correlations of C and one positive correlation of N with
respect to the He abundance. We found a clear C abundance dichotomy
where approximately 82% of the stars show N enrichment above the solar
value. Moreover, we observed a bimodal distribution of C abundances,
prominently evident in both the Galactic thin and thick disks but
absent in the halo population. Furthermore, we found that the scenario
of the merger channel of double helium white dwarfs is inadequate to
explain the formation of C-deficient He-rich hot subdwarfs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 280 210 Atmospheric parameters, Galactic velocities, and
orbital parameters for He-rich hot subdwarf stars
observed in Gaia DR3 and LAMOST DR7
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See also:
V/156 : LAMOST DR7 catalogs (Luo+, 2019)
I/352 : Distances to 1.47 billion stars in Gaia EDR3 (Bailer-Jones+, 2021)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/A+A/400/877 : White dwarfs 3D kinematics from SPY project (Pauli+, 2003)
J/A+A/447/173 : 3D-kinematics of WDs from SPY project. II. (Pauli+, 2006)
J/MNRAS/427/2180 : GALEX survey subdwarf atmospheric parameters (Nemeth+, 2012)
J/ApJ/868/70 : Hot subdwarf stars from Gaia DR2 and LAMOST DR5 (Lei+, 2018)
J/A+A/630/A130 : Co-added spectra of HD127493 and HZ44 (Dorsch+, 2019)
J/ApJ/881/135 : Hot subdwarfs from GaiaDR2 & LAMOST DR5. II. (Lei+, 2019)
J/ApJ/881/7 : Hot subdwarf stars from LAMOST DR5 & Gaia DR2 (Luo+, 2019)
J/A+A/643/A22 : UVES spectra of Feige 46 and LSIV -14 116 (Dorsch+, 2020)
J/A+A/635/A193 : Catalogue of hot subdwarf stars DR2 (Geier, 2020)
J/ApJ/889/117 : Hot subdwarfs from Gaia DR2 & LAMOST DR6+7. I. (Lei+, 2020)
J/ApJ/898/64 : Hot subdwarfs from Gaia with LAMOST sp. II. RVs (Luo+, 2020)
J/MNRAS/491/874 : Abundances of hot subdwarfs with Subaru (Naslim+, 2020)
J/ApJS/256/28 : Hot subdwarfs with Gaia DR2 and LAMOST DR7 data (Luo+, 2021)
Byte-by-byte Description of file: table3.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 Ep=2000
32- 39 F8.5 deg DEdeg [-6.2/76] Barycentric Declination
(ICRS) at Ep=2000
41- 46 I6 K Teff [12690/105590] Stellar effective
temperature
48- 52 I5 K e_Teff [10/10280] Standard error in Teff
54- 57 F4.2 [cm/s2] logg [3.7/9.8] Log stellar surface gravity
59- 62 F4.2 [cm/s2] e_logg [0/4.6] Standard error in logg
64- 68 F5.2 [Sun] log(nHe/nH) [-4.4/4] Stellar surface log He
abundance
70- 73 F4.2 [Sun] e_log(nHe/nH) [0/1.1] Standard error in log (nHe/nH)
75- 79 F5.2 [Sun] log(nC/nH) [-7/2.3] Stellar surface log C
abundance
81- 84 F4.2 [Sun] e_log(nC/nH) [0/2.2] Standard error in log (nC/nH)
86- 90 F5.2 [Sun] log(nN/nH) [-6/1.24] Stellar surface log N
abundance
92- 96 F5.2 [Sun] e_log(nN/nH) [0/14] Standard error in log (nN/nH)
98- 102 F5.2 [-] log(beta-He) [-3.8/0] Log mass fraction of surface
He abundance (1)
104- 107 F4.2 [-] e_log(beta-He) [0/1.5] Standard error in log (beta-He)
109- 113 F5.2 [-] log(beta-C) [-7/-0.78] Log mass fraction of
surface C abundance (1)
115- 118 F4.2 [-] e_log(beta-C) [0.02/2.2] Standard error in log
(beta-C)
120- 124 F5.2 [-] log(beta-N) [-6/-1.4] Log mass fraction of surface
N abundance (1)
126- 130 F5.2 [-] e_log(beta-N) [0/14] Standard error in log (beta-N)
132- 134 I3 km/s vsini [5/758] Rotational velocity
136- 138 I3 km/s e_vsini [4/250] Standard error in vsini
140- 145 F6.2 mas/yr pmRA [-87.2/82] Gaia EDR3 proper motion in
RA
147- 150 F4.2 mas/yr e_pmRA [0.02/0.9] Standard error pmRA
152- 157 F6.2 mas/yr pmDE [-97.5/31] Gaia EDR3 proper motion in
DE
159- 162 F4.2 mas/yr e_pmDE [0.02/0.6] Standard error in pmDE
164- 168 I5 pc dist [192/10560] Gaia EDR3 stellar distance
170- 173 I4 pc e_dist [2/4106] Standard error in dist
175- 178 I4 km/s RVel [-334/173] Radial velocity from LAMOST
DR7 spectra
180- 182 I3 km/s e_RVel [1/150] Standard error in RVel
184- 187 I4 km/s U [-297/352] Galactic radial velocity
positive towards Galactic center
189- 190 I2 km/s e_U [0/72] Standard error in U
192- 195 I4 km/s V [-174/309] Galactic rotational
velocity along Galactic rotation
197- 199 I3 km/s e_V [0/121] Standard error in V
201- 204 I4 km/s W [-179/198] Galactic velocity towards
north Galactic pole
206- 207 I2 km/s e_W [0/70] Standard error in W
209- 213 F5.2 kpc Rap [5.5/33.07] Apocenter radius (2)
215- 219 F5.2 kpc e_Rap [0/25.7] Standard error in Rap
221- 225 F5.2 kpc Rperi [0.07/14] Pericenter radius (2)
227- 230 F4.2 kpc e_Rperi [0.01/5] Standard error in Rperi
232- 235 F4.2 kpc zmax [0.02/1] Maximum vertical height (2)
237- 240 F4.2 kpc e_zmax [0/0.2] Standard error in zmax
242- 246 F5.2 --- ecc [0.09/28.1] Eccentricity (2)
248- 252 F5.2 --- e_ecc [0/21.8] Standard error in ecc
254- 258 I5 kpc/km/s Jz [-1770/3141] Z-component of angular
momentum (2)
260- 263 I4 kpc/km/s e_Jz [1/1324] Standard error in Jz
265 I1 --- Pops [0/2] Population classification (3)
267- 270 F4.2 % p(TH) [0/1] Probability in thin disk
272- 275 F4.2 % p(TK) [0/1] Probability in thick disk
277- 280 F4.2 % p(H) [0/1] Probability in halo
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Note (1): Where beta-I=(mI/(mH+mHe+mC+mN), and I=He, C and N.
Note (2): From the numerical orbit integration.
Note (3): 0 is thin disk, 1 is thick disk, and 2 are the Halo.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 24-Apr-2024