J/ApJ/936/5 LAMOST parameters for 188 white dwarfs (Wang+, 2022)
Extremely Low-mass White Dwarf Stars Observed in Gaia DR2 and LAMOST DR8.
Wang K., Nemeth P., Luo Y., Chen X., Jiang Q., Cao X.
<Astrophys. J., 936, 5 (2022)>
=2022ApJ...936....5W 2022ApJ...936....5W
ADC_Keywords: Stars, white dwarf; Spectra, optical; Effective temperatures;
Radial velocities; Stars, masses; Stars, diameters
Keywords: White dwarf stars ; Compact objects
Abstract:
We present the first results from our ongoing project to study
extremely low-mass (ELM) white dwarfs (WDs) (M≲0.3M☉) with the
Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST)
spectra. Based on the LAMOST DR8 spectral database, we analyzed 136
ELM WD candidates selected from Gaia DR2 data and 12 known objects
previously identified by the ELM Survey. The atmospheric parameters
and radial velocities of these stars were obtained by fitting the
LAMOST low-resolution spectra. After comparing the atmospheric
parameters of the 12 known objects from this work to the results
reported by the ELM Survey, we demonstrated the potential of LAMOST
spectra in probing into the nature of ELM WDs. Based on the
atmospheric parameters and Gaia EDR3 data, we identified 21 new
high-probability ELM WDs with masses M≲0.3M☉ and parallax
estimates that agree to within a factor of 3. Two of them, J0338+4134
and J1129+4715, show significant radial velocity variability and are
very likely to be binary systems containing at least one ELM WD.
Description:
The LAMOST telescope, specialized for conducting spectroscopic
surveys, is situated at the Xinglong Station of National Astronomical
Observatory, Chinese Academy of Sciences. LAMOST data consist of two
components: data from the low-resolution spectroscopic survey (LRS;
R∼1800) covering the wavelength range of 3800-9100AA, and data from
the medium-resolution spectroscopic survey (MRS; R∼7500).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 109 188 Measured parameters for the 188 LAMOST
low-resolution spectra
table2.dat 89 19 Comparison of the atmospheric parameters from this
work to the results published in ELM survey paper
table3.dat 106 21 Physical parameters of the 21 high-probability
ELM WDs
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See also:
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
V/146 : LAMOST DR1 catalogs (Luo+, 2015)
J/A+A/339/123 : PSR J1012+5307 evolutionary tracks (Driebe+ 1998)
J/ApJ/723/1072 : The ELM survey. I. Low-mass white dwarfs (Brown+, 2010)
J/ApJ/730/128 : Spectroscopy of DA WD from the SDSS-DR4 (Tremblay+, 2011)
J/MNRAS/427/2180 : GALEX survey subdwarf atmospheric params (Nemeth+, 2012)
J/A+A/557/A19 : Mass & age extreme low-mass white dwarfs (Althaus+, 2013)
J/A+A/595/A35 : Low-mass He white dwarfs evolutionary (Istrate+, 2016)
J/MNRAS/455/3413 : White dwarf & subdwarf stars in SDSS DR12 (Kepler+, 2016)
J/MNRAS/469/2102 : White dwarf pop from the SDSS DR12 (Anguiano+, 2017)
J/A+A/617/A6 : Seven new pulsating sdA stars (Bell+, 2018)
J/MNRAS/488/2892 : Gaia DR2 extremely low-mass WD cands (Pelisoli+, 2019)
J/ApJ/889/49 : ELM Survey. VIII. Final double WD binaries (Brown+, 2020)
J/ApJ/894/53 : ELM Survey South. I. RVs for 6 ELM WDs (Kosakowski+, 2020)
J/ApJS/256/28 : Hot subdwarf stars Gaia DR2 & LAMOST DR7 data (Luo+, 2021)
J/other/RAA/21.292 : LAMOST Time-Domain survey, first results (Wang+, 2021)
J/A+A/661/A113 : Hot subdwarf * Radial velocity variability (Geier+, 2022)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Object Object short name
12- 21 F10.6 deg RAdeg [0/354] Right Ascension (J2000)
23- 31 F9.6 deg DEdeg [-3/67] Declination (J2000)
33- 38 I6 K Teff [7570/114540] Surface effective temperature
40- 44 I5 K e_Teff [40/31380] Uncertainty in Teff
46- 46 A1 --- l_logg Limit flag on logg
49- 53 F5.3 [cm/s2] logg [2.058/8.796] log, surface gravity
55- 59 F5.3 [cm/s2] e_logg [0.01/1.716]? Uncertainty in logg
61- 61 A1 --- l_y Limit flag on y
64- 69 F6.3 [-] y [-5.689/1.69] log, nHe/nH
71- 75 F5.3 [-] e_y [0.001/1.767]? Uncertainty in y
77- 82 F6.1 km/s RVel [-448.5/351.6] Radial velocity
84- 88 F5.1 km/s e_RVel [1.9/150.0] Uncertainty in RVel
90- 93 F4.1 --- SNRg [10.2/97.8] Signal-to-noise in g-band
95-109 A15 --- Notes Notes (1)
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Note (1): Notes as follows:
[A-F] = grade of the fit quality in descending order, which correlates
with the SNR and the spectral types of the objects;
BOSZ = Spectra were fitted with LTE models (Bohlin+, 2017AJ....153..234B 2017AJ....153..234B)
PET = Spectra were fitted with ELM WD models (Tremblay+, 2015ApJ...809..148T 2015ApJ...809..148T)
pg1159 = PG1159-type objects, hot H-deficient pre-WDs en route to the
WD cooling sequence;
met = Spectra that show metal lines (Na I, Mg I, and Ca II);
neb = Spectra that show nebular lines;
comp = Composite spectrum binaries, or double-lined binaries;
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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- 10 A10 --- Object Object short name
12- 12 A1 --- Flag a=MMT spectra provided by
Dr. Warren R. Brown
15- 24 F10.6 deg RAdeg [12/240] Right Ascension (J2000)
26- 35 F10.6 deg DEdeg [-13/52] Declination (J2000)
37- 41 I5 K Teff-XTgrid [7570/21160] Surface effective
temperature, XTgrid
43- 45 I3 K e_Teff-XTgrid [50/680] Uncertainty in Teff-XTgrid
47- 47 A1 --- l_logg-XTgrid Limit flag on logg-XTgrid
50- 54 F5.3 [cm/s2] logg-XTgrid [4.905/7.474] log, surface gravity,
XTgrid
56- 60 F5.3 [cm/s2] e_logg-XTgrid [0.01/0.233]? Uncertainty in logg-XTgrid
62- 67 A6 --- XTgrid-model Model atmosphere used in XTgrid (1)
69- 73 I5 K Teff-B20 [8096/21660] Surface effective
temperature, Brown+, 2020, J/ApJ/889/49
75- 77 I3 K e_Teff-B20 [100/380] Uncertainty in Teff-B20
79- 83 F5.3 [cm/s2] logg-B20 [5.045/7.76] log, surface gravity,
Brown+, 2020, J/ApJ/889/49
85- 89 F5.3 [cm/s2] e_logg-B20 [0.041/0.112] Uncertainty in logg-B20
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Note (1): Models as follows:
BOSZ = Spectra were fitted with LTE models (Bohlin+, 2017AJ....153..234B 2017AJ....153..234B)
PET = Spectra were fitted with ELM WD models (Tremblay+, 2015, J/ApJ/809/148)
Tlusty = Tlusty non-LTE models, Hubeny & Lanz, 2017arXiv170601859H 2017arXiv170601859H
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Object Object short name
12- 21 F10.6 deg RAdeg [14/354] Right Ascension (J2000)
23- 31 F9.6 deg DEdeg [-3/51] Declination (J2000)
33- 37 I5 K Teff [9390/26680] Surface effective temperature
39- 42 I4 K e_Teff [40/3110] Uncertainty in Teff
44- 48 F5.3 [cm/s2] logg [4.667/7.21] log, surface gravity
50- 54 F5.3 [cm/s2] e_logg [0.037/0.367] Uncertainty in logg
56- 60 F5.3 Msun Mass [0.159/0.334] Mass, solar units
62- 66 F5.3 Msun e_Mass [0.011/0.07] Uncertainty in Mass
68- 72 F5.3 Rsun Rad [0.024/0.36] Radius, solar units
74- 78 F5.3 Rsun e_Rad [0.003/0.078] Uncertainty in Radius
80- 85 F6.4 mas plx-gaia [0.1469/6.2726] Parallax, Gaia EDR3
87- 92 F6.4 mas e_plx-gaia [0.0283/0.1644] Uncertainty in plx-gaia
94- 99 F6.4 mas plx-spec [0.3702/2.7432] Spectroscopic parallax,
Equation 3
101-106 F6.4 mas e_plx-spec [0.0408/1.4252] Uncertainty in plx-spec
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 17-Jun-2024