J/ApJ/898/64 Hot subdwarf stars from Gaia with LAMOST sp. II. RVs (Luo+, 2020)
Hot subdwarf stars identified in Gaia DR2 with spectra of LAMOST DR6 and DR7.
II. Kinematics.
Luo Y., Nemeth P., Li Q.
<Astrophys. J., 898, 64 (2020)>
=2020ApJ...898...64L 2020ApJ...898...64L
ADC_Keywords: Stars, subdwarf; Radial velocities; Space velocities; Optical
Keywords: Stellar kinematics ; Subdwarf stars
Abstract:
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 JZ- 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 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)<-2.2 from the common envelope ejection channel, and He-rich
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.
Description:
We utilized the spectra of LAMOST DR6 and DR7 to measure the radial
velocities of the 182 single-lined hot subdwarf stars observed in Gaia
DR2 and LAMOST DR6 and DR7 (Paper I; Lei+ 2020, J/ApJ/889/117). The
LAMOST spectra are similar to the SDSS data with a resolution of
R∼1800 and wavelength coverage of 3800-9100Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 307 182 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
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See also:
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
V/164 : LAMOST DR5 catalogs (Luo+, 2019)
J/A+A/400/939 : Stellar parameters of 115 HQS sdB stars (Edelmann+, 2003)
J/A+A/400/877 : White dwarfs 3D kinematics from SPY project (Pauli+, 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/A+A/530/A28 : Priority targets for the MUCHFUSS project (Geier+, 2011)
J/MNRAS/427/2180 : GALEX survey subdwarf atmospheric parameters (Nemeth+, 2012)
J/A+A/551/A31 : New spectral classif. for hot subdwarfs (Drilling+, 2013)
J/A+A/569/A15 : KIC 10553698A asteroseismology (Ostensen+, 2014)
J/A+A/577/A26 : Radial velocities of hot subluminous stars (Geier+, 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/other/RAA/16.G7 : Nearby M subdwarfs from LAMOST DR2 (Bai+, 2016)
J/A+A/616/A10 : 46 open clusters GaiaDR2 HR diag. (Gaia Collaboration, 2018)
J/A+A/616/A12 : Gaia DR2 sources in GC and dSph (Gaia Collaboration+, 2018)
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/A+A/621/A38 : Gaia catalogue of hot subluminous stars (Geier+, 2019)
J/ApJS/240/31 : M-subdwarf research. I. LAMOST DR4 spectra obs. (Zhang+, 2019)
J/ApJ/889/117 : Hot subdwarf stars from GaiaDR2 & LAMOST. I. (Lei+, 2020)
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 DR6+7 target
21- 31 F11.7 deg RAdeg Barycentric Right Ascension (ICRS)
at Epoch=2000.0
33- 42 F10.7 deg DEdeg [-3.1/82] Barycentric Declination (ICRS)
at Epoch=2000.0
44- 48 I5 K Teff [22230/79240] Stellar effective
temperature (2)
50- 54 I5 K e_Teff [10/11150] Standard error in Teff
56- 59 F4.2 [cm/s2] logg [5/6.9] Stellar surface gravity (2)
61- 64 F4.2 [cm/s2] e_logg [0/0.8] Standard error in logg
66- 70 F5.2 [Sun] log(y) [-3.5/2.81] Stellar surface He abundance
y=n(He)/n(H) (2)
71- 71 A1 --- l_log(y) Upper limit flag on log(y)
73- 76 F4.2 [Sun] e_log(y) [0.01/1.04]? Standard error in log(y),
null for upper limits
78- 84 A7 --- SpT Spectral type (2)
86- 92 F7.3 mas/yr pmRA [-32.3/24.12] Proper motion in RA
94- 98 F5.3 mas/yr e_pmRA [0.04/0.7] Standard error pmRA
100-106 F7.3 mas/yr pmDE [-32.84/17] Proper motion in DE
108-112 F5.3 mas/yr e_pmDE [0.04/0.5] Standard error in pmDE
114-117 I4 pc dist [279/8850] Gaia DR2 stellar distance
119-122 I4 pc e_dist [6/8427] Standard error in dist
124-127 I4 km/s RVel [-352/206] Radial velocity from LAMOST spectra
129-130 I2 km/s e_RVel [12/78] Standard error in RVelal velocity
132-138 F7.3 kpc X [-13.4/-4.3] Galactic position
towards Galactic center
140-144 F5.3 kpc e_X [0.002/2.9] Standard error in X
146-151 F6.3 kpc Y [-3.6/7.1] Galactic position
along Galactic rotation
153-157 F5.3 kpc e_Y [0.001/4.1] Standard error of Y
159-164 F6.3 kpc Z [-3.2/6.3] Galactic position
towards north Galactic pole
166-170 F5.3 kpc e_Z [0.001/3.1] Standard error of Z
172-175 I4 km/s U [-317/257] Galactic radial velocity
positive towards Galactic center
177-179 I3 km/s e_U [1/198] Standard error in U
181-184 I4 km/s V [-301/328] Galactic rotational velocity
along Galactic rotation
186-188 I3 km/s e_V [0/275] Standard error in V
190-193 I4 km/s W [-336/162] Galactic velocity
towards north Galactic pole
195-197 I3 km/s e_W [0/215] Standard error in W
199-204 F6.2 kpc Rap [5.9/446.2] Apocenter radius (3)
206-211 F6.2 kpc e_Rap [0.02/499] Standard error in Rap
213-217 F5.2 kpc Rperi [0.06/14.3] Pericenter radius (3)
219-222 F4.2 kpc e_Rperi [0.01/8.5] Standard error in Rperi
224-229 F6.2 kpc zmax [0.09/372] Maximum vertical height (3)
231-236 F6.2 kpc e_zmax [0.01/472] Standard error in zmax
238-241 F4.2 --- e [0.01/0.99] Eccentricity (3)
243-246 F4.2 --- e_e [0.01/0.22] Standard error in e
248-255 F8.2 kpc/km/s Jz [-3515/2972] Z-component of angular
momentum (3)
257-263 F7.2 kpc/km/s e_Jz [8.3/2962] Standard error in Jz
265-268 F4.2 --- zn [0.01/8.5] Normalised z-extent of the
orbit (3)
270-274 F5.2 --- e_zn [0/38.5] Standard error in zn
276-277 A2 --- Pop Population classification (4)
279-280 I2 % p(TH) [0/95] Probability in thin disk
282-283 I2 % p(TK) [0/99] Probability in thick disk
285-287 I3 % p(H) [0/100] Probability in halo
289-307 I19 --- Gaia Gaia DR2 identifier from Paper I
(Lei+ 2020, J/ApJ/889/117);
column added by CDS
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Note (2): From Paper I (Lei+ 2020, J/ApJ/889/117).
Note (3): From the numerical orbit integration.
Note (4): Population classification as follows:
H = Halo (26 occurrences);
Tk = thick disk (73 occurrences);
TH = thin disk (83 occurrences).
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History:
From electronic version of the journal
References:
Luo et al. Paper I. 2020ApJ...889..117L 2020ApJ...889..117L Cat. J/ApJ/889/117
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 18-Nov-2021