J/ApJS/253/22 Ks absolute magnitudes from LAMOST for OB stars (Xiang+, 2021)
Data-driven spectroscopic estimates of absolute magnitude, distance, and
binarity: method and catalog of 16002 O- and B-type stars from LAMOST.
Xiang M., Rix H.-W., Ting Y.-S., Zari E., El-badry K., Yuan H.-B.,
Cui W.-Y.
<Astrophys. J. Suppl. Ser., 253, 22-22 (2021)>
=2021ApJS..253...22X 2021ApJS..253...22X (SIMBAD/NED BibCode)
ADC_Keywords: Stars, OB; Radial velocities; Magnitudes, absolute;
Proper motions; Stars, distances; Parallaxes, trigonometric;
Photometry, infrared
Keywords: OB stars; Early-type stars; Emission line stars; Stellar distance
Binary stars; Spectroscopic binary stars; Absolute magnitude
Astronomical methods; Astronomy data modeling
Principal component analysis; Neural networks; Catalogs
Abstract:
We present a data-driven method to estimate absolute magnitudes for
O- and B-type stars from the LAMOST spectra, which we combine with
Gaia DR2 parallaxes to infer distance and binarity. The method applies
a neural network model trained on stars with precise Gaia parallax to
the spectra and predicts Ks-band absolute magnitudes MKs with a
precision of 0.25mag, which corresponds to a precision of 12% in
spectroscopic distance. For distant stars (e.g., >5kpc), the inclusion
of constraints from spectroscopic MKs significantly improves the
distance estimates compared to inferences from Gaia parallax alone.
Our method accommodates for emission-line stars by first identifying
them via principal component analysis reconstructions and then
treating them separately for the MKs estimation. We also take into
account unresolved binary/multiple stars, which we identify through
deviations in the spectroscopic MKs from the geometric MKs
inferred from Gaia parallax. This method of binary identification is
particularly efficient for unresolved binaries with near equal-mass
components and thus provides a useful supplementary way to identify
unresolved binary or multiple-star systems. We present a catalog of
spectroscopic MKs, extinction, distance, flags for emission lines,
and binary classification for 16002 OB stars from LAMOST DR5. As an
illustration, we investigate the MKs of the enigmatic LB-1 system,
which Liu et al. 2019Natur.575..618L 2019Natur.575..618L had argued consists of a B star
and a massive stellar-mass black hole. Our results suggest that LB-1
is a binary system that contains two luminous stars with comparable
brightness, and the result is further supported by parallax from the
Gaia eDR3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 382 27752 Distance catalog for 16002 OB stars in LAMOST DR5
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See also:
V/116 : Galactic O star catalog (Maiz-apellaniz+, 2004)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
III/284 : APOGEE-2 data from DR16 (Johnsson+, 2020)
J/ApJ/608/405 : Explosive yields of massive star (Chieffi+, 2004)
J/A+A/423/755 : Color-Induced Displacement double SDSS stars (Pourbaix+, 2004)
J/A+A/430/137 : Close visual companions in Scorpius OB2 (Kouwenhoven+, 2005)
J/ApJ/663/320 : IR-through-UV extinction curve (Fitzpatrick+, 2007)
J/ApJS/190/1 : A survey of stellar families (Raghavan+, 2010)
J/other/Sci/337.444 : RV curves of Galactic massive O stars (Sana+, 2012)
J/A+A/550/A107 : RV catalogue of O stars in 30 Doradus (Sana+, 2013)
J/AJ/148/81 : APASS BVgri photometry of RAVE stars. I. Data (Munari+, 2014)
J/ApJS/228/24 : GALAH semi-automated classification scheme (Traven+, 2017)
J/AJ/153/257 : Comoving stars in Gaia DR1 (Oh+, 2017)
J/MNRAS/472/675 : Wide binaries in Tycho-Gaia: search method (Andrews+, 2017)
J/A+A/608/A95 : GES: multi-line spectroscopic binary candidates (Merle+, 2017)
J/A+A/615/A78 : Spectral models for binary products (Goetberg+, 2018)
J/A+A/616/A10 : Open clusters Gaia DR2 HR diagrams (Gaia Collaboration, 2018)
J/A+A/616/L15 : Parallaxes and Proper Motions of OB stars (Xu+, 2018)
J/AJ/156/45 : M-dwarf multiples in the SDSS-III/APOGEE (Skinner+, 2018)
J/A+A/623/A72 : Binarity of HIP stars from Gaia pm anomaly (Kervella+, 2019)
J/ApJS/241/32 : OB stars from the LAMOST DR5 spectra (Liu+, 2019)
J/AJ/158/147 : Spectrophotometric parallaxes with linear models (Hogg+, 2019)
J/ApJS/245/34 : Abundances for 6 million stars from LAMOST DR5 (Xiang+, 2019)
J/A+A/638/A76 : StarHorse data for 5 surveys (Queiroz+, 2020)
J/A+A/638/A145 : GALAH survey. FGK binary stars (Traven+, 2020)
J/A+A/639/L6 : HERMES spectra of LS V +22 25 (Shenar+, 2020)
J/ApJS/249/22 : Radial velocity variable stars from LAMOST DR4 (Tian+, 2020)
J/ApJS/249/31 : Short period spec. & EBs from LAMOST & PTF (Yang+, 2020)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Seq [1/27752] Index number
7- 16 F10.6 deg RAdeg LAMOST DR5 Right Ascension in decimal
degrees (J2000)
18- 26 F9.6 deg DEdeg LAMOST DR5 Right Ascension in decimal
degrees (J2000)
28- 29 I2 --- Uniq [1/25] Flag to indicate repeat visits (1)
31- 35 F5.1 --- SNR-g [0/999] Spectral signal-to-noise ratio per
pixel in SDSS g-band
37- 42 F6.1 km/s RVel [-707/999]?=-999 LAMOST radial velocity
44- 48 F5.1 km/s e_RVel [0.1/999]?=0 Uncertainty in RVel
50- 55 F6.2 mag KsMag [-5.7/3.3]?=-99 Spectroscopic absolute Ks
band magnitude
57- 62 F6.2 mag e_KsMag [0/100]?=0 Uncertainty in KsMag
64- 69 F6.2 mag KsMaggeo [-11.3/12.3]?=-99 Geometric absolute Ks
band magnitude (3)
71- 75 F5.2 mag e_KsMaggeo [0.01/18]?=0 Uncertainty in KsMaggeo
77- 83 F7.1 kpc Dist [36/60775]?=0 Distance at mode in
cumulative probability distribution function
85- 91 F7.1 kpc e_Dist [36/51274]?=0 Lower 16% pdf value in Dist
93- 99 F7.1 kpc E_Dist [37/86458]?=0 Upper 84% pdf value in Dist
101- 107 F7.5 [kpc] logD [1.5/4.8]?=0 PDF-weighted mean log distance
109- 115 F7.5 [kpc] e_logD [5e-5/1.3]?=0 Uncertainty logD
117- 120 F4.2 mag E(B-V) [0/2.6] The (B-V) color excess
122- 127 F6.2 mag e_E(B-V) [0.01/999] Uncertainty in E (B-V)
129- 134 F6.2 --- snr-plx [-99/24] Excess in spectro-photometric
parallax (4)
136- 137 I2 --- Bin [-9/1]? Flag of binarity (5)
139 I1 --- em [0/1] Flag of emission lines
(1=with emission lines)
141- 159 I19 --- Gaia ? Gaia DR2 source identifier
161- 168 F8.4 mas plx [-12.4/27.1] Gaia DR2 parallax
170- 175 F6.4 mas e_plx [0/1.6] Uncertainty in plx
177- 183 F7.4 mas Offset [-0.056/0] Offset of Gaia parallax (7)
185- 192 F8.3 mas/yr pmRA [-128/109] Gaia DR2 proper motion along RA
194- 198 F5.3 mas/yr e_pmRA [0/3.5] Uncertainty in pmRA
200- 207 F8.3 mas/yr pmDE [-125/48] Gaia DR2 proper motion along DE
209- 213 F5.3 mas/yr e_pmDE [0/2.3] Uncertainty in pmDE
215- 220 F6.2 --- ruwe [-99/65] Gaia DR2 renormalised unit weight
error (ruwe) value
222- 227 F6.3 mag Jmag [5.4/16.9]?=0 Apparent 2MASS J band magnitude
229- 233 F5.3 mag e_Jmag [0/0.2] Uncertainty in Jmag
235- 240 F6.3 mag Hmag [4.8/17.8]?=0 Apparent 2MASS H band magnitude
242- 246 F5.3 mag e_Hmag [0/10] Uncertainty in Hmag
248- 253 F6.3 mag Ksmag [4.4/17.6]?=0 Apparent 2MASS Ks band
magnitude
255- 259 F5.3 mag e_Ksmag [0/10] Uncertainty in Ksmag
261- 266 F6.2 kpc X [-62.3/10.9] Cartesian coordinate X
Galactic position (8)
268- 273 F6.2 kpc Y [-16.1/37.6] Cartesian coordinate Y
Galactic position (8)
275- 280 F6.2 kpc Z [-31.6/28.6] Cartesian coordinate Z
Galactic position (8)
282- 317 A36 --- specID LAMOST spectra identifier (9)
319- 333 A15 --- starID A unique ID for each unique star based on
position (10)
335- 382 A48 --- FileName Name of the LAMOST spectral file in FITS
format
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Note (1): Where 1 indicates a unique star subsequent numbers indicate
the nth repeat visit.
Note (3): Inferred from Gaia parallaxes and 2MASS apparent magnitudes.
Note (4): With respect to the Gaia astrometric parallax.
Note (5): Flag as follows:
1 = binary (snr dparallax ≥2);
0 = single (snr dparallax <2);
-9 = unknown.
Note (7): According to the offset - G magnitude relation of
Leung & Bovy (2019MNRAS.489.2079L 2019MNRAS.489.2079L).
Note (8): The Sun is placed at X=-8.1, Y=0, Z=0.
Note (9): In the format of "date-planid-spid-fiberid".
Note (10): Based on its RA and Dec, in the format of "Sdddmmss+ddmmss".
Note added by CDS: right ascensions seem not right.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 03-May-2021