J/A+A/662/A66 Hot stars from LAMOST DR6 (Xiang+, 2022)
Stellar labels for hot stars from low-resolution spectra.
I. the HotPayne method and results for 330000 stars from LAMOST DR6.
Xiang M., Rix H.-W., Ting Y.-S., Kudritzki R.-P., Conroy C., Zari E.,
Shi J.-R., Przybilla N., Ramirez-Tannus M., Tkachenko A., Gebruers S.,
Liu X.-W.
<Astron. Astrophys. 662, A66 (2022)>
=2022A&A...662A..66X 2022A&A...662A..66X (SIMBAD/NED BibCode)
ADC_Keywords: Stars, early-type ; Effective temperatures ; Abundances ;
Rotational velocities ; Photometry ; Optical ;
Photometry, infrared
Keywords: techniques: spectroscopic - surveys - catalogs - stars: massive -
stars: fundamental parameters - stars: abundances -
Abstract:
We set out to determine stellar labels from low-resolution survey
spectra of hot stars, specifically OBA stars with Teff≳7500K. This
fills a gap in the scientific analysis of large spectroscopic stellar
surveys such as LAMOST, which offers spectra for millions of stars at
R∼1800 and covering 3800Å-9000Å. We first explore the
theoretical information content of such spectra for determining
stellar labels, via the Cramer-Rao bound. We show that in the limit
of perfect model spectra and observed spectra with S/N∼50-100, precise
estimates are possible for a wide range of stellar labels: not only
the effective temperature Teff, surface gravity logg, and projected
rotation velocity vsini, but also the micro-turbulence velocity vmic ,
Helium abundance NHe=Ntot and the elemental abundances [C/H], [N/H],
[O/H], [Si/H], [S/H], and [Fe/H]. Our analysis illustrates that the
temperature regime of Teff∼9500K is challenging, as the dominant
Balmer and Paschen line strength vary little with Te . We implement
the simultaneous fitting of these 11 stellar labels to LAMOST hot-star
spectra using the PAYNE approach, drawing on Kurucz's ATLAS12/SYNTHE
LTE spectra as the underlying models. We then obtain stellar parameter
estimates for a sample of about 330000 hot stars with LAMOST spectra,
an increase by about two orders of magnitude in sample size. Among
them, about 260000 have S/N>5 Gaia parallaxes, and their luminosities
imply that ≳95% among them are luminous star, mostly on the main
sequence; the rest reflects lower luminosity evolved stars, such as
hot subdwarfs and white dwarfs. We show that the fidelity of the
results, particularly for the abundance estimates, is limited by the
systematics of the underlying models, as they do not account for NLTE
effects. Finally, we show the detailed distribution of v sin i of
stars with 8000-15000K, illustrating that it extends to a sharp
cut-off at the critical rotation velocity, vcrit, across a wide range
of temperatures.
Description:
Our stellar parameter catalog contains Teff, logg, vsini, [Fe/H],
and [Si/H] for 332172 unique stars with Teff>7000K and S/N>5 from
454693 spectra of LAMOST DR6.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 741 454693 Stellar label catalog for hot stars in LAMOST DR6
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See also:
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/328 : AllWISE Data Release (Cutri+ 2013)
Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 36 A36 --- SpecID LAMOST spectra ID,
date-planid-spid-fiberid
38- 47 F10.6 deg RAdeg Right ascension from the
LAMOST DR6 catalog (J2000)
49- 57 F9.6 deg DEdeg Declination from the
LAMOST DR6 catalog (J2000)
59- 64 F6.2 --- snrg Pixel spectral signal-to-noise ratio
in SDSS g-band
66- 72 F7.1 K Teff Effective temperature
74- 85 E12.6 K e_Teff Uncertainty in Teff
87- 97 F11.6 [cm/s2] logg Surface gravity
99-110 E12.6 [cm/s2] e_logg Uncertainty in logg
112-122 F11.6 [-] [Fe/H] Iron abundance
124-135 E12.6 [-] e_[Fe/H] Uncertainty in [Fe/H]
137-144 F8.3 km/s vsini ?=-999 Projected rotation velocity
146-157 E12.6 km/s e_vsini Uncertainty in vsini
159-169 F11.6 [-] [Si/H] Silicon abundance
171-182 E12.6 [-] e_[Si/H] Uncertainty in [Si/H]
184-192 F9.6 --- corTeff-logg ?=- Correlation coefficient between
teff and logg, derived from the
covariance array of the fit
194-202 F9.6 --- corTeff-[Fe/H] ?=- Correlation coefficient between
Teff and [Fe/H]
204-212 F9.6 --- corlogg-[Fe/H] ?=- Correlation coefficient between
logg and [Fe/H]
214-222 F9.6 --- corTeff-vsini ?=- Correlation coefficient between
Teff and vsini
224-232 F9.6 --- corlogg-vsini ?=- Correlation coefficient between
logg and vsini
234-242 F9.6 --- corvsini-[Fe/H] ?=- Correlation coefficient between
vsini and [Fe/H]
244-252 F9.6 --- corTeff-[Si/H] ?=- Correlation coefficient between
Teff and [Si/H]
254-262 F9.6 --- corlogg-[Si/H] ?=- Correlation coefficient between
logg and [Si/H]
264-272 F9.6 --- cor[Si/H]-[Fe/H] ?=- Correlation coefficient between
[Si/H] and [Fe/H]
274-282 F9.6 --- corvsini-[Si/H] ?=- Correlation coefficient between
vsini and [Si/H]
284-295 E12.6 --- chisqred Chi square of the fit divided by dof
297-305 F9.3 km/s RV ?=-99999 Line-of-sight velocity
from LAMOST 1D pipeline
307-318 E12.6 km/s e_RV [] Uncertainty in RV
320-331 E12.6 --- chi2ratio Deviation of the chisqred from the
median value
333-334 I2 --- uniqflag [1/32] Flag to indicate repeat
visits; 1 means the first (unique)
visit, n(>1) means the n-th repeat
visit
336-350 A15 --- StarID Star ID, defined in format of
SDDDMMSS+DDMMSS for stars of similar
S/N and Teff, divided by the
dispersion
352 I1 --- sourceDR6oba [0/1] Is this target from the LAMOST
DR6 classification? (1='YES', 0='NO')
354 I1 --- sourceZari21 [0/1] Is this target from the
photometric identification with Zari
et al. (2021, in prep.)'s method?
(1='YES', 0='NO')
356 I1 --- sourceLiu19 [0/1] Is this target from the OB star
catalog of Liu et al.
(2019ApJ...881....7L 2019ApJ...881....7L)?
(1='YES', 0='NO')
358-376 I19 --- GaiaEDR3 ?=0 Source ID of Gaia eDR3
378-388 F11.6 mas Plx ?=- Gaia eDR3 parallax
390-397 F8.6 mas e_Plx ?=- Uncertainty in parallax
399-409 F11.6 mas/yr pmRA ?=- Gaia eDR3 proper motion in RA
direction
411-418 F8.6 mas/yr e_pmRA ?=- Uncertainty in pmRA
420-430 F11.6 mas/yr pmDE ?=- Gaia eDR3 proper motion in Dec
direction
432-439 F8.6 mas/yr e_pmDE ?=- Uncertainty in pmDE
441-449 F9.6 --- RUWE ?=- Gaia eDR3 RUWE
451-465 F15.8 pc rgeo ?=0 Geometric distance based on Gaia
parallax from Bailer-Jones et al.
(2021, Cat. I/352)
467-480 F14.8 pc e_rgeo ?=0 Distance at 16th percentile of
the PDF area
482-495 F14.8 pc E_rgeo ?=0 Distance at 84th percentile of
the PDF area
497-504 F8.6 --- Fidelity ?=- Fidelity value from Rybizki et al.
(2021, in prep.), an identifier for
spurious astrometric solutions
506-513 F8.6 mag E(B-V)bayes19 ?=- E(B-V) interpolated from the 3D
map of Green et al.
(2019ApJ...887...93G 2019ApJ...887...93G) using rgeo
515-524 F10.6 mag E(B-V)pair ?=- E(B-V) estimated using
intrinsic color from synthetic
spectra of HotPayne stellar
parameters
526-535 F10.6 mag e_E(B-V)pair ?=- Uncertainty in E(B-V)pair
537-545 F9.6 mag Gmag ?=- Gaia eDR3 magnitude in G band
547-554 F8.6 mag e_Gmag ?=- Uncertainty in Gmag
556-564 F9.6 mag BPmag ?=- Gaia eDR3 magnitude in BP band
566-573 F8.6 mag e_BPmag ?=- Uncertainty in BPmag
575-583 F9.6 mag RPmag ?=- Gaia eDR3 magnitude in RP band
585-592 F8.6 mag e_RPmag ?=- Uncertainty in RPmag
594-602 F9.6 mag Jmag ?=- 2MASS magnitude in J band
604-611 F8.6 mag e_Jmag ?=- Uncertainty in Jmag
613-621 F9.6 mag Hmag ?=- 2MASS magnitude in H band
623-630 F8.6 mag e_Hmag ?=- Uncertainty in Hmag
632-640 F9.6 mag Kmag ?=- 2MASS magnitude in K band
642-649 F8.6 mag e_Kmag ?=- Uncertainty in Kmag
651-653 A3 --- Q-2MASS 2MASS photometric quality flag
655-663 F9.6 mag W1mag ?=- WISE magnitude in W1 band
665-672 F8.6 mag e_W1mag ?=- Uncertainty in W1mag
674-682 F9.6 mag W2mag ?=- WISE magnitude in W2 band
684-691 F8.6 mag e_W2mag ?=- Uncertainty in W2mag
693-702 F10.6 mag W3mag ?=- WISE magnitude in W3 band
704-711 F8.6 mag e_W3mag ?=- Uncertainty in W3mag
713-722 F10.6 mag W4mag ?=- WISE magnitude in W4 band
724-731 F8.6 mag e_W4mag ?=- Uncertainty in W4mag
733-736 A4 --- Q-WISE WISE photometric quality flag
738-741 A4 --- VAR-WISE WISE variability flag
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Acknowledgements:
Maosheng Xiang, mxiang(at)mpia.de
(End) Patricia Vannier [CDS] 27-Feb-2022