J/ApJS/234/31 Carbon stars from LAMOST using machine learning (Li+, 2018)
Carbon stars identified from LAMOST DR4 using machine learning.
Li Y.-B., Luo A.-L., Du C.-D., Zuo F., Wang M.-X., Zhao G., Jiang B.-W.,
Zhang H.-W., Liu C., Qin L., Wang R., Du B., Guo Y.-X., Wang B., Han Z.-W.,
Xiang M.-S., Huang Y., Chen B.-Q., Chen J.-J., Kong X., Hou W., Song Y.-H.,
Wang Y.-F., Wu K.-F., Zhang J.-N., Zhang Y., Wang Y.-F., Cao Z.-H.,
Hou Y.-H., Zhao Y.-H.
<Astrophys. J. Suppl. Ser., 234, 31 (2018)>
=2018ApJS..234...31L 2018ApJS..234...31L
ADC_Keywords: Stars, carbon ; Abundances, [Fe/H] ; Photometry, ugriz ;
Infrared ; Ultraviolet ; Proper motions ; Spectral types ;
Radial velocities
Keywords: catalogs; methods: data analysis; methods: statistical; stars: carbon;
surveys
Abstract:
In this work, we present a catalog of 2651 carbon stars from the
fourth Data Release (DR4) of the Large Sky Area Multi-Object Fiber
Spectroscopy Telescope (LAMOST). Using an efficient machine-learning
algorithm, we find these stars from more than 7 million spectra. As a
by-product, 17 carbon-enhanced metal- poor turnoff star candidates are
also reported in this paper, and they are preliminarily identified by
their atmospheric parameters. Except for 176 stars that could not be
given spectral types, we classify the other 2475 carbon stars into
five subtypes: 864 C-H, 226 C-R, 400 C-J, 266 C-N, and 719 barium
stars based on a series of spectral features. Furthermore, we divide
the C-J stars into three subtypes, C-J(H), C-J(R), and C-J(N), and
about 90% of them are cool N-type stars as expected from previous
literature. Besides spectroscopic classification, we also match these
carbon stars to multiple broadband photometries. Using ultraviolet
photometry data, we find that 25 carbon stars have FUV detections and
that they are likely to be in binary systems with compact white dwarf
companions.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table6.dat 76 17 Equatorial coordinates, S/Ns, atmospheric
parameters, and spectral types of the 17
carbon-enhanced metal-poor (CEMP) turnoff star
candidates
table7.dat 95 17 Ultraviolet, optical, and infrared magnitudes of
the 17 CEMP turnoff star candidates
table8.dat 68 17 Radial velocities and proper motions of the 17
CEMP turnoff star candidates
table11.dat 417 2651 Basic parameters, photometry, and proper motions
of the carbon stars
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See also:
III/156 : Cool Galactic Carbon Stars, 2nd Edition (Stephenson 1989)
III/227 : General Catalog of galactic Carbon stars, 3d Ed. (Alksnis+ 2001)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
I/317 : The PPMXL Catalog (Roeser+ 2010)
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
V/149 : LAMOST DR2 catalogs (Luo+, 2016)
I/343 : Gaia-PS1-SDSS (GPS1) proper motion catalog (Tian+, 2017)
J/AJ/90/2089 : Stars of very low metal abundance. I (Beers+, 1985)
J/AJ/103/1987 : Stars of very low metal abundance (Beers+ 1992)
J/ApJS/105/419 : Spectral Atlas of Carbon Stars (Barnbaum+ 1996)
J/AZh/76/604 : Spectrophotometry of S and carbon stars (Tereshchenko, 1999)
J/A+A/375/366 : Carbon stars from the Hamburg/ESO survey (Christlieb+ 2001)
J/AJ/124/1651 : Faint high-lat. carbon stars SDSS photometry (Margon+, 2002)
J/AJ/127/2838 : Faint high-lat. carbon stars SDSS photometry (Downes+, 2004)
J/A+A/532/A54 : GRAMS carbon-star model grid (Srinivasan+, 2011)
J/ApJ/765/12 : Carbon stars and DQ WDs from SDSS-DR7+DR8 (Green, 2013)
J/other/RAA/15.1671 : New carbon stars from LAMOST survey (Si+, 2015)
J/MNRAS/459/4299 : Barium stars abundances and kinematics (de Castro+, 2016)
J/A+A/589/A36 : Carbon stars spectra and photometry values (Gonneau+, 2016)
J/ApJS/226/1 : Carbon stars from LAMOST DR2 data (Ji+, 2016)
http://dr4.lamost.org/ : LAMOST DR4 home page
Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1-19 A19 --- LAMOST LAMSOT-DR4 star identifier (JHHMMSS.ss+DDMMSS.s)
21-30 F10.6 deg RAdeg Right ascension (J2000)
32-40 F9.6 deg DEdeg Declination (J2000)
42-44 I3 --- S/N [23/160] r-band signal-to-noise ratio
46-49 I4 K Teff [5624/6068] Effective temperature
51-52 I2 K e_Teff [21/50] Teff uncertainty
54-57 F4.2 [cm/s2] logg [3.3/4.1] Log of surface gravity
59-62 F4.2 [cm/s2] e_logg [0.03/0.1] logg uncertainty
64-68 F5.2 [-] [Fe/H] [-2.5/-1.3] Metallicity
70-73 F4.2 [-] e_[Fe/H] [0.03/0.07] Uncertainty of [Fe/H]
75-76 A2 --- SpT MK spectral type given by the LAMOST 1D pipeline
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- LAMOST Star identifier (JHHMMSS.ss+DDMMSS.s)
21- 23 A3 mag FUVmag ? GALEX FUV magnitude (always blank)
25- 29 F5.2 mag NUVmag [16.1/20.6]? GALEX NUV magnitude
31- 35 F5.2 mag umag [14.5/18.5]? SDSS u-band AB magnitude
37- 41 F5.2 mag gmag [13.6/17.6]? SDSS g-band AB magnitude
43- 47 F5.2 mag rmag [13.3/17.3]? SDSS r-band AB magnitude
49- 53 F5.2 mag imag [13.5/17.2]? SDSS i-band AB magnitude
55- 59 F5.2 mag zmag [13.2/17.2]? SDSS z-band AB magnitude
61- 65 F5.2 mag Jmag [12.4/16.3] 2MASS J-band magnitude
67- 71 F5.2 mag Hmag [12.1/15.8] 2MASS H-band magnitude
73- 77 F5.2 mag Ksmag [12.1/15.8] 2MASS Ks-band magnitude
79- 83 F5.2 mag W1mag [12/16] WISE W1 (3.4um) magnitude
85- 89 F5.2 mag W2mag [12.1/16.1] WISE W2 (4.6um) magnitude
91- 95 F5.2 mag W3mag [11.7/12.9] WISE W3 (12um) magnitude
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1-19 A19 --- LAMOST Star identifier (JHHMMSS.ss+DDMMSS.s)
21-24 I4 km/s RV [-337/283] Radial velocity
26 I1 km/s e_RV [1/4] Radial velocity uncertainty
28-32 F5.1 mas/yr pmRA-p [-62/54] PPMXL proper motion along RA
(µαcos(δ))
34-36 F3.1 mas/yr e_pmRA-p [3/5] pmRA uncertainty
38-42 F5.1 mas/yr pmDE-p [-74/56] PPMXL proper motion along DE
(µ_δ)
44-46 F3.1 mas/yr e_pmDE-p [3/5] pmDE uncertainty
48-52 F5.1 mas/yr pmRA-u [-64/55]? UCAC4 proper motion along RA
(µαcos(δ))
54-57 F4.1 mas/yr e_pmRA-u [1/18]? pmRA uncertainty
59-63 F5.1 mas/yr pmDE-u [-77/55]? UCAC4 proper motion along DE
(µ_δ)
65-68 F4.1 mas/yr e_pmDE-u [1/19]? pmDE uncertainty
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Byte-by-byte Description of file: table11.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- --- [LAMOST]
8- 26 A19 --- LAMOST LAMOST-DR4 identifier (JHHMMSS.ss+DDMMSS.s)
28- 37 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
39- 47 F9.6 deg DEdeg Declination in decimal degrees (J2000)
49- 51 I3 --- SNR [0/910] Signal to noise ratio in r band
53- 60 A8 --- Class MK spectral type from LAMOST 1D pipeline
62- 65 A4 --- New? "new": a new carbon star (1415 occurrences)
67- 72 A6 --- Type Source type (1)
74- 85 A12 --- SpType MK type of carbon star (2)
87- 94 F8.2 mag FUVmag [19/25.2]?=-9999 GALEX FUV band magnitude
96-103 F8.2 mag e_FUVmag [0.06/0.6]?=-9999 Error in FUVmag
105-112 F8.2 mag NUVmag [14.5/24.6]?=-9999 GALEX NUV band magnitude
114-121 F8.2 mag e_NUVmag [0/1.7]?=-9999 Error in NUVmag
123-130 F8.2 mag gmag [9.8/21.8]?=-9999 Pan-STARRS g band AB mag
132-139 F8.2 mag e_gmag [0/0.4]?=-9999 Error in gmag
141-148 F8.2 mag rmag [7.7/19]?=-9999 Pan-STARRS r band AB mag
150-157 F8.2 mag e_rmag [0/0.5]?=-9999 Error in rmag
159-166 F8.2 mag imag [7/20.1]?=-9999 Pan-STARRS i band AB mag
168-175 F8.2 mag e_imag [0/0.5]?=-9999 Error in imag
177-184 F8.2 mag zmag [6.3/20]?=-9999 Pan-STARRS z band AB mag
186-193 F8.2 mag e_zmag [0/0.5]?=-9999 Error in zmag
195-202 F8.2 mag ymag [4.9/18.8]?=-9999 Pan-STARRS y band AB mag
204-211 F8.2 mag e_ymag [0/0.5]?=-9999 Error in ymag
213-220 F8.2 mag Jmag [3.9/17]?=-9999 2MASS J band magnitude
222-229 F8.2 mag e_Jmag [0.02/0.4]?=-9999 Error in Jmag
231-238 F8.2 mag Hmag [2.5/16.7]?=-9999 2MASS H band magnitude
240-247 F8.2 mag e_Hmag [0.01/9]?=-9999 Error in Hmag
249-256 F8.2 mag Ksmag [1.1/16.7]?=-9999 2MASS Ks band magnitude
258-265 F8.2 mag e_Ksmag [0.01/10]?=-9999 Error in Ksmag
267-274 F8.2 mag W1mag [-2/16.5]?=-9999 WISE W1 (3.4um) band magnitude
276-283 F8.2 mag e_W1mag [0.02/0.6]?=-9999 Error in W1mag
285-292 F8.2 mag W2mag [-2/16.6]?=-9999 WISE W2 (4.6um) band magnitude
294-301 F8.2 mag e_W2mag [0.02/0.6]?=-9999 Error in W2mag
303-310 F8.2 mag W3mag [-3/13.4]?=-9999 WISE W3 (12um) band magnitude
312-319 F8.2 mag e_W3mag [0.01/0.6]?=-9999 Error in W3mag
321-327 F7.1 mas/yr pmRA-p [-195/207]?=-9999 PPMXL catalog proper motion
in Right Ascension
329-335 F7.1 mas/yr e_pmRA-p [0.8/21]?=-9999 Error in pmRA-p
337-343 F7.1 mas/yr pmDE-p [-317/137]?=-9999 PPMXL proper motion in
Declination
345-351 F7.1 mas/yr e_pmDE-p [0.8/21]?=-9999 Error in pmDE-p
353-359 F7.1 mas/yr pmRA-u [-187/153]?=-9999 UCAC4 catalog proper motion
in Right Ascension
361-367 F7.1 mas/yr e_pmRA-u [0.5/50]?=-9999 Error in pmRA-u
369-375 F7.1 mas/yr pmDE-u [-308/107]?=-9999 UCAC4 proper motion in
Declination
377-383 F7.1 mas/yr e_pmDE-u [0.5/50]?=-9999 Error in pmDE-u
385-391 F7.1 mas/yr pmRA-t [-49/59]?=-9999 GAIA TGAS catalog proper motion
in Right Ascension
393-399 F7.1 mas/yr e_pmRA-t [0.1/6]?=-9999 Error in pmRA-t
401-407 F7.1 mas/yr pmDE-t [-46/32]?=-9999 GAIA TGAS catalog proper motion
in Declination
409-415 F7.1 mas/yr e_pmDE-t [0.1/5]?=-9999 Error in pmDE-t
417 A1 --- Bin Binary candidate that likely has compact white
dwarf companion (see table 13; column added
by CDS)
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Note (1): Type as follows:
EM = emission line star (93 occurrences),
G_type = G-type star (308 occurrences)
Binary = star with composite spectrum (12 occurrences);
otherwise "NULL" (2238 occurrences).
Note (2): Including the C-H, C-R, C-J,C-N and Ba types.
Classification criteria of carbon stars (table 1):
----------------------------------------------------------------------------
Subtype Criteria
----------------------------------------------------------------------------
C-H (1) Prominence of the secondary P-branch head near 4342Å
(2) Strong CH band
(3) Hβ and BaII at 4554Å are clearly noticeable
(4) Hα and BaII at 6496Å are noticeable
(5) Blend feature of NaI D1 and NaI D2 is not distinguishable
(6) CaI at 4226Å is marginally noticeable
C-R (1) Strong CaI at 4226Å
(2) NaI D1 and NaI D2 blended lines have two distinct dips
(3) Weak Hβ and BaII at 4554Å blended with atomic and
molecular lines
(4) Weak Hα and BaII at 6496Å blended with the CN bands
around 6500Å
C-N (1) No flux at λ<4400Å; some very late-type C-N can be
flat even at λ<5000Å
(2) Strong BaII at 6496Å
(3) Weak Hα and isotopic C bands
C-J (1) A high isotope ratio of 13C to 12C with j index ≥4
Ba (1) Barium star. Strong lines of s-process elements,
particularly BaII at 4554Å and SrII at 4077Å
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EM = emission-lines
UNKNOWN = stars for which we cannot give a spectral type
NULL = stars that cannot be classified
For C-J stars, we set four values for them. "C-J(H)," "C-J(R)," "C-J(N),"
and "C-J(UNKNOWN)," respectively represent C-H, C-R, C-N, and unknown stars
with unusually strong isotopic carbon bands.
See section 4.1 for further explanations.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-Mar-2018