J/ApJS/260/35 Classical Be stars from LAMOST MRS DR7 (Wang+, 2022)
Identification of new classical Be stars from the LAMOST Medium Resolution
Survey.
Wang L., Li J., Wu Y., Gies D.R., Liu J.Z., Liu C., Guo Y., Chen X., Han Z.
<Astrophys. J. Suppl. Ser., 260, 35 (2022)>
=2022ApJS..260...35W 2022ApJS..260...35W
ADC_Keywords: Stars, Be; Spectra, optical; Surveys; Spectral types;
Photometry, infrared; Proper motions; Clusters, open
Keywords: Early-type stars ; Be stars ; Surveys
Abstract:
Be stars are B-type main-sequence stars that display broad Balmer
emission lines in their spectra. Identification of the Be population
is essential to further examine the formation and evolutionary models.
We report the detection of classical Be (CBe) stars from observations
with the Large sky Area Multi- Object fiber Spectroscopic Telescope
Medium Resolution Survey Data Release 7 (LAMOST MRS DR7). We used a
deep convolutional neural network, ResNet, with an 18 layer module to
examine the morphology of the Hα profile. We identified 1162
candidate Be stars from the collection of 2,260,387 spectra for
789,918 stars in the database. The ResNet network achieves a Be-star
classification accuracy of 99.5%. Among the detections, 151 of these
are prior known Be stars crossmatched from the literature. By applying
a three-step test, we identified 183 new CBe stars. We find that 41
CBe stars are members of known open clusters. Based on an
investigation of the kinematics of the identified CBe stars from the
Gaia EDR3 astrometric solutions, we identified 16 new runaways. These
new identifications will provide a reference for future follow-ups to
further investigate their physical properties.
Description:
We obtained the optical spectra from the Large sky Area Multi-Object
fiber Spectroscopic Telescope (LAMOST), also known as the Guoshoujing
Telescope, at the Xinlong station of the National Astronomical
Observatory. LAMOST began the new five-year Medium Resolution Survey
(MRS; R=7500 with a wavelength range of 4950-5350Å for the blue arm
and 6300-6800Å for the red arm) in 2018 October.
We downloaded a total collection of 2,260,387 spectra of early-type
stars with a signal-to-noise ratio (S/N) greater than 10 per pixel in
both blue and red bands from the LAMOST DR7. The observations were
made on nights between 2018 October and 2019 June.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 42 1042 Be candidate spectra selected for the training sample
table3.dat 42 1042 Non-Be candidate spectra selected for the
training sample
table5.dat 77 8 Oe stars found from the LAMOST MRS DR7 sample
table6.dat 77 151 Known Be stars found from the MRS sample
table7.dat 137 183 Newly identified classical Be (CBe) stars from the
LAMOST MRS DR7 sample
table8.dat 89 41 Open cluster memberships for identified CBe stars
from the LAMOST MRS DR7 sample
table9.dat 79 16 The peculiar velocities of the 16 runaway CBe stars
identified from the LAMOST MRS DR7 sample
tablea1.dat 38 113 Candidate Be stars displaying Ha emission profiles
with absorption shell line identified
from the LAMOST MRS DR7 sample
tablea2.dat 38 199 Candidate Be stars displaying Ha absorption profiles
with shell line identified from the LAMOST MRS DR7
sample
refs.dat 61 85 References
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See also:
B/mk : Catalogue of Stellar Spectral Classifications (Skiff, 2009- )
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/328 : AllWISE Data Release (Cutri+ 2013)
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
I/352 : Distances to 1.47 billion stars in Gaia EDR3 (Bailer-Jones+, 2021)
V/125 : Photometry and Spectroscopy for Luminous Stars (Reed 2005)
V/156 : LAMOST DR7 catalogs (Luo+, 2019)
J/ApJS/94/687 : Old stellar populations. V. (Worthey+, 1994)
J/A+A/331/949 : Wolf-Rayet and O-star runaways kinematics (Moffat+ 1998)
J/AJ/126/2971 : UBVRI photometry of 131 Herbig Ae/Be (Vieira+, 2003)
J/MNRAS/360/974 : Proper motionsof pulsars (Hobbs+, 2005)
J/A+A/461/631 : Counterparts to massive X-ray binaries (Negueruela+, 2007)
J/ApJ/686/1280 : Discovery of hot subdwarf comp. to FY CMa (Peters+, 2008)
J/MNRAS/384/1277 : Hα emission line sources from IPHAS (Witham+, 2008)
J/MNRAS/410/190 : Young runaway stars within 3kpc (Tetzlaff+, 2011)
J/other/RAA/11.924 : Atmospheric parameters for 771 stars (Wu+, 2011)
J/AJ/144/158 : B and Be stars in h and χ Persei (Marsh+, 2012)
J/ApJ/765/2 : FUV radial velocities of 59 Cyg (Peters+, 2013)
J/AJ/149/7 : SDSS-III/APOGEE. I. Be stars (Chojnowski+, 2015)
J/other/RAA/15.1325 : Be stars in LAMOST DR1 (Lin+, 2015)
J/MNRAS/463/1162 : Infrared photometry of Be stars (Chen+, 2016)
J/A+A/591/A140 : IPHAS-selected classical Be stars (Gkouvelis+, 2016)
J/ApJ/828/47 : Radial velocities of the Be star HR 2142 (Peters+, 2016)
J/MNRAS/465/1807 : Deep OB star population in Carina (Mohr-Smith+, 2017)
J/A+A/618/A93 : Gaia DR2 open clusters in the MW (Cantat-Gaudin+, 2018)
J/A+A/638/A21 : Herbig Ae/Be & classical Be stars catalog (Vioque+, 2020)
J/MNRAS/504/356 : Updated parameters of 1743 open clusters (Dias+, 2021)
J/ApJ/909/149 : Be star omega CMa V LC & polarimetry (Ghoreyshi+, 2021)
J/ApJS/253/54 : Galactic O-type stars from LAMOST spectra (Li, 2021)
J/MNRAS/503/3279 : GALAH survey: Gal. disc with open clusters (Spina+, 2021)
Byte-by-byte Description of file: table[23].dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- ObsID [589703181/719603123] LAMOST spectrum OBSID
11- 18 F8.4 deg RAdeg [0.016/113.4] Right Ascension (J2000)
20- 26 F7.4 deg DEdeg [3.6/66.4] Declination (J2000)
28- 37 F10.4 d MJD [58025.15/58507.81] Observational date
39- 42 I4 --- S/N [47/539] S/N of the spectrum
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Byte-by-byte Description of file: table[56].dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- LAMOST LAMOST designation (JHHMMSS.ss+DDMMSS.s)
21- 45 A25 --- Name Common star identifier
47- 54 F8.4 deg RAdeg Right Ascension (J2000)
56- 62 F7.4 deg DEdeg [-5.5/63.6] Declination (J2000)
64- 74 A11 --- SpType Spectral type
76- 77 I2 --- r_SpType [1/85]? Reference for SpType (see refs.dat file)
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- LAMOST LAMOST designation (JHHMMSS.ss+DDMMSS.s)
21- 47 A27 --- Name Star name
49- 56 F8.4 deg RAdeg Right Ascension (J2000)
58- 64 F7.4 deg DEdeg [-6.3/64] Declination (J2000)
66- 76 A11 --- SpType Spectral type
78- 79 I2 --- r_SpType [1/65] Reference for SpType (see refs.dat file)
81- 86 F6.3 mag Jmag [7.15/12.46] AllWISE apparent J magnitude
88- 92 F5.3 mag e_Jmag [0.017/0.05] Uncertainty in Jmag
94- 99 F6.3 mag Hmag [6.76/12.34] AllWISE apparent H magnitude
101-105 F5.3 mag e_Hmag [0.014/0.07] Uncertainty in H mag
107-112 F6.3 mag Kmag [6.54/12.22] AllWISE apparent K magnitude
114-118 F5.3 mag e_Kmag [0.013/0.05] Uncertainty in Kmag
120-125 F6.3 mag W1mag [6.36/12.04] AllWISE W1 magnitude
127-131 F5.3 mag e_W1mag [0.02/0.14] Uncertainty in W1mag
133-137 F5.3 mag E(B-V) [0.02/2.3] Reddening
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Byte-by-byte Description of file: table8.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- LAMOST LAMOST designation (JHHMMSS.ss+DDMMSS.s)
21- 33 A13 --- Cluster Cluster name (1)
35- 39 F5.1 km/s RV [-84.3/92.3]? Cluster radial velocity, Vr (1)
41- 43 F3.1 km/s e_RV [0.2/3.1]? Uncertainty in RV
45- 48 I4 pc Dist [707/3158] Distance (1)
50- 52 I3 pc e_Dist [7/290] Uncertainty in Dist
54- 58 F5.3 yr logAge [7/8.83] log of cluster age (1)
60- 64 F5.3 yr e_logAge [0.02/0.65] Uncertainty in Age
66- 71 F6.3 [-] [Fe/H] [-0.22/0.3] Cluster metallicity (1)
73- 77 F5.3 [-] e_[Fe/H] [0.047/0.2] Uncertainty in [Fe/H]
79- 83 F5.3 mag Av [0.9/2.8] Extinction coefficient (1)
85- 89 F5.3 mag e_Av [0.019/0.2] Uncertainty in Av
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Note (1): From Dias et al. J/MNRAS/504/356
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Byte-by-byte Description of file: table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- LAMOST LAMOST designation (JHHMMSS.ss+DDMMSS.s)
21- 27 F7.4 mas/yr pmRA [-4.6/4.2] Gaia EDR3 proper motion
in Right Ascension, µα
29- 34 F6.4 mas/yr e_pmRA [0.01/0.04] Uncertainty in pmPA
36- 42 F7.4 mas/yr pmDE [-6.9/0.91] Gaia EDR3 proper motion
in Declination, µβ
44- 49 F6.4 mas/yr e_pmDE [0.01/0.03] Uncertainty in pmDE
51- 56 F6.4 mas plx [0.1/0.8] Gaia EDR3 parallax
58- 63 F6.4 mas e_plx [0.01/0.03] Uncertainty in plx
65- 68 F4.1 km/s VTp [24.7/48.8] Tangential peculiar velocity
70- 72 F3.1 km/s e_VTp [0.9/3.6] Uncertainty in VTp
74- 79 F6.2 pc Z [31.5/295.8] Height from the Galactic plane
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Byte-by-byte Description of file: tablea[12].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- LAMOST LAMOST designation (JHHMMSS.ss+DDMMSS.s)
21- 28 F8.4 deg RAdeg Right Ascension (J2000)
30- 36 F7.4 deg DEdeg [-7.7/66.4] Declination (J2000)
38 I1 --- Ind [1/3] Morphological classification type (1)
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Note (1): Type index as follows:
1 = shell-line spectra with an emission component above the spectral continuum
2 = emission component below the spectral continuum
3 = narrow absorption shell line
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference code
4-22 A19 --- BibCode ADS bibcode of the reference
24-36 A13 --- Auth First author's name
38-61 A24 --- Comm VizieR catalog reference
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 02-Aug-2022