J/ApJ/908/131 M-subdwarf research. II. Catalog of ∼3000 subdwarfs (Zhang+, 2021)
M-subdwarf research.
II. Atmospheric parameters and kinematics.
Zhang S., Luo A.-L., Comte G., Wang R., Li Y.-B., Du B., Hou W., Qin Li,
Gizis J., Chen J.-J., Chen X.-L., Lu Y., Song Y.-H., Zhang H.-W., Zuo F.
<Astrophys. J., 908, 131 (2021)>
=2021ApJ...908..131Z 2021ApJ...908..131Z
ADC_Keywords: Stars, M-type; Stars, subdwarf; Spectra, optical; Proper motions;
Radial velocities; Parallaxes, trigonometric
Keywords: M subdwarf stars
Abstract:
We applied the revised M subdwarf classification criteria discussed in
Zhang+ 2019, J/ApJS/240/31 (Paper I) to Large Sky Area Multi-Object
Fiber Spectroscopic Telescope (LAMOST) DR7 and combined the result
with the M subdwarf sample from Savcheva+ 2014ApJ...794..145S 2014ApJ...794..145S to
construct a new M subdwarf sample for further study. The atmospheric
parameters for each object were derived from fitting to the PHOENIX
grid, and the sources with available astrometry and photometry from
Gaia DR2 were combined for further analysis. The relationship between
the gravity and metallicity was explored according to the locus both
in the color-absolute magnitude diagram and the reduced proper motion
diagram. Objects that have both the largest gravity and the lowest
metallicity are located away from the main-sequence cloud and may be
considered as the intrinsic M subdwarfs, which can be classified as
luminosity class VI. Another group of objects whose spectra show
typical M subdwarf characteristics have lower gravity and relatively
moderate metal deficiency and occupy part of the ordinary M dwarf
region in both diagrams. The Galactic U, V, W space velocity
components and their dispersion show that the local Galactic halo
population sampled in the solar neighborhood is represented by objects
of high gravity and an inconspicuous bimodal metallicity distribution,
with a fraction of prograde orbits. The other M subdwarfs seem to
belong in part to the thick disk component, with a significant
fraction of thin disk, moderately metal-poor objects intricately mixed
with them. However, selection effects, especially the favored
anticenter direction of investigation in the LAMOST subsample, as well
as contamination by multiplicity and parameter coupling, could play
important roles and need to be investigated further.
Description:
The low-resolution spectra of M dwarfs and subdwarfs are from LAMOST
DR7 and SDSS DR7, and the astrometric data is from Gaia DR2.
LAMOST is a reflecting Schmidt telescope located at the Xinglong
Station of the National Astronomical Observatory, China, with a mean
aperture of 4.3m and a field of view of 5deg. A total of 4000 optical
fibers positioned on the focal plane yield a high spectrum acquisition
rate per night. Until 2020 March, DR7 published more than 10 million
low-resolution spectra (R∼1800) covering 3800-9000Å and 2.17
million medium resolution spectra (R∼7500) covering 3700-5900Å and
5700-9000Å.
SDSS DR7 was collected by a dedicated wide-field 2.5m telescope at
Apache Point Observatory. The telescope employed a drift-scan
technique, imaging the sky in u, g, r, i, and z wide bands along five
camera columns. The fiber-fed spectrographs acquired 640 spectra
(R∼2000) simultaneously, and the spectral range is 3800-9200Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 863 3131 Subdwarf catalog
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See also:
VII/195 : Globular Clusters in the Milky Way (Harris, 1996)
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
III/198 : Palomar/MSU nearby star spectroscopic survey (Hawley+ 1997)
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
V/156 : LAMOST DR7 catalogs (Luo+, 2019)
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/AJ/113/806 : M-Subdwarfs (Gizis 1997)
J/A+A/410/527 : Abundances in the Galactic disk (Bensby+, 2003)
J/AJ/125/1598 : High proper motion stars in northern sky (Lepine+, 2003)
J/MNRAS/340/304 : [X/Fe] of Galactic disc F and G dwarfs (Reddy+, 2003)
J/PASP/115/22 : Stellar parameters for 134 cool subdwarfs (Yong+, 2003)
J/AJ/128/426 : Subdwarfs in the SDSS (West+, 2004)
J/AJ/130/1658 : High proper motion stars (-47<delta<00) (Subasavage+, 2005)
J/AJ/137/1 : Proper motions & astrom late-type dwarfs (Faherty+, 2009)
J/AJ/143/67 : SLoWPoKES. II. Prop wide, low-mass binaries (Dhital+, 2012)
J/AJ/145/102 : Spectro of bright Mdwarfs in northern sky (Lepine+, 2013)
J/A+A/564/A90 : Msubdwarfs VLT/UVES high res spectra (Rajpurohit+, 2014)
J/AJ/150/42 : Catalog of 2612 M dwarfs from LAMOST (Zhong+, 2015)
J/ApJ/804/30 : Robo-AO observed cool subdwarf companions (Ziegler+, 2015)
J/other/RAA/16.G7 : Nearby M subdwarfs from LAMOST DR2 (Bai+, 2016)
J/ApJ/836/77 : Library of high-S/N opt spectra of FGKM stars (Yee+, 2017)
J/A+A/616/A10 : 46 open clusters GaiaDR2 diagram (Gaia Collaboration, 2018)
J/A+A/620/A180 : Stellar properties of M dwarfs (Rajpurohit+, 2018)
J/MNRAS/480/5447 : New L subdwarfs, population properties (Zhang+, 2018)
J/AJ/157/63 : Rad relations low-metallicity Mdwarf stars (Kesseli+, 2019)
J/ApJS/240/31 : Msubdwarf research. I. LAMOST DR4 obs. (Zhang+, 2019)
J/AJ/159/30 : High proper-motion M-type stars spectro (Hejazi+, 2020)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- ID Designation for the stellar object (1)
21- 60 A40 --- SpecID Name of spectrum
62- 72 F11.7 deg RAdeg Right Ascension (J2000)
74- 84 F11.7 deg DEdeg [-18/79] Declination (J2000)
86- 106 F21.17 deg GLON [0/360] Galactic longitude
108- 128 F21.17 deg GLAT [-80/89] Galactic latitude
130- 136 F7.1 km/s HRV [-300/299]? Heliocentric radial velocity
138- 144 F7.1 K Teff [2800/4500]? Estimated effective temperature
146- 153 F8.2 [cm/s2] logg [2/5.94]? Estimated surface gravity
155- 162 F8.2 [-] [Fe/H] [-2.5/0.44]? Estimated overall metallicity
164- 168 F5.1 --- SNRi [2/207] Average spectrum signal to noise
ratio in i band
170- 171 I2 --- SpT [-2/9] Spectral subtype
173- 192 F20.17 --- CaOH [-0.62/1.36] Spectral index of CaOH band
194- 212 F19.17 --- CaH1 [0.0002/1.19] Spectral index of CaH1 band
214- 232 F19.17 --- CaH2 [0.14/0.89] Spectral index of CaH2 band
234- 252 F19.17 --- CaH3 [0.23/1.04] Spectral index of CaH3 band
254- 272 F19.17 --- TiO5 [0.3/1.43] Spectral index of TiO5 band
274- 295 F22.19 --- ZetaL07 [-2.04/0.91] The value of Zeta parameter
calibrated by Lepine+, 2007ApJ...669.1235L 2007ApJ...669.1235L
297- 318 F22.19 --- ZetaD12 [-1.26/0.79] The value of Zeta parameter
calibrated by Dhital+, 2012, J/AJ/143/67
320- 341 F22.19 --- ZetaL13 [-2.11/0.83] The value of Zeta parameter
calibrated by Lepine+, 2013, J/AJ/145/102
343- 364 F22.19 --- ZetaZ19 [-1.51/0.75] The value of Zeta parameter
calibrated by Zhang+ 2019, J/ApJS/240/31
(Paper I)
366- 371 A6 --- Inst The source of spectrum ("lamost" or "sdss")
373- 394 F22.18 mas plx [-6.75/132]? Gaia DR2 parallax
396- 415 F20.18 mas e_plx [0.01/3]? Standard error of Gaia DR2 parallax
417- 439 F23.18 mas/yr pmRA [-6428/1128]? Gaia DR2 proper motion in
right ascension direction
441- 460 F20.18 mas/yr e_pmRA [0.01/5]? Standard error of Gaia DR2 proper
motion in right ascension direction
462- 484 F23.17 mas/yr pmDE [-1074/253]? Gaia DR2 proper motion in
declination direction
486- 505 F20.18 mas/yr e_pmDE [0.01/4]? Standard error of Gaia DR2 proper
motion in declination direction
507- 529 F23.19 --- Good [-4.7/551]? Goodness of fit statistic of
model wrt along-scan observations
531- 552 E22.20 --- Sig [0/87996]? Significance of excess noise
554- 573 F20.15 mag GFluxE [46.3/5633]? G-band mean flux divided by its
error (phot-g-mean-flux-over-error)
575- 592 F18.15 mag Gmag [8.2/21.3]? Gaia DR2 G-band mean magnitude
594- 613 F20.16 mag BpFluxE [0.89/987]? Integrated BP mean flux divided
by its error
615- 632 F18.15 mag Bpmag [9.28/22.2]? Gaia DR2 integrated BP mean
magnitude
634- 654 F21.16 mag RpFluxE [6.19/1938]? Integrated RP mean flux divided
by its error
656- 673 F18.15 mag Rpmag [7.19/20]? Gaia DR2 integrated RP mean
magnitude
675- 692 F18.16 mag Bp-Rp [0.62/3.17]? Gaia DR2 BP-RP color
694- 712 F19.16 --- RUWE [0.77/37.2]? Renormalized Unit Weight Error
associated to each Gaia source
714- 732 F19.14 pc Rest [43.9/3757]? Estimated distance from Gaia DR2
734- 736 F3.1 --- ResFl [1]? The Result Flag from Gaia DR2
738- 740 F3.1 --- ModFl [1]? The Modality Flag from Gaia DR2
742- 744 F3.1 --- Flag [0/1]? Set as 1 for the final sample used in
kinematic part, see table 3 for details
746- 766 F21.16 km/s Vtot [2.88/4773]? Total spacial velocity
768- 789 F22.16 pc Z [-1658/2172]? Vertical distance away from
Galactic plane
791- 814 F24.19 km/s U [-745/3630]? Velocity component points
towards the galactic center
816- 839 F24.18 km/s V [-2459/153]? The tangential velocity
component rotating around galactic center
841- 863 F23.18 km/s W [-314/1898]? Velocity component points to
wards the north galactic pole
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Note (1): The identifier provided corresponds either to the SDSS DR7 SpecObjID
or to the LAMOST obsids.
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History:
From electronic version of the journal
References:
Zhang et al. Paper I. 2019ApJS..240...31Z 2019ApJS..240...31Z Cat. J/ApJS/240/31
Zhang et al. Paper III. 2023ApJ...942...40Z 2023ApJ...942...40Z
(End) Prepared by [AAS], Coralie Fix [CDS], 13-Feb-2024