J/ApJ/765/12 Carbon stars and DQ white dwarfs from SDSS-DR7+DR8 (Green, 2013)
Innocent bystanders: carbon stars from the Sloan Digital Sky Survey.
Green P.
<Astrophys. J., 765, 12 (2013)>
=2013ApJ...765...12G 2013ApJ...765...12G
ADC_Keywords: Photometry, SDSS ; Stars, carbon ; Stars, white dwarf ;
Photometry, infrared ; Photometry, ultraviolet ; Proper motions
Keywords: astrometry; stars: carbon; stars: statistics; surveys
Abstract:
Among stars showing carbon molecular bands (C stars), the
main-sequence dwarfs, likely in post-mass transfer binaries, are
numerically dominant in the Galaxy. Via spectroscopic selection from
the Sloan Digital Sky Survey, we retrieve 1220 high galactic latitude
C stars, ∼5 times more than previously known, including a wider
variety than past techniques such as color or grism selection have
netted, and additionally yielding 167 DQ white dwarfs. Of the C stars
with proper motion measurements, we identify 69% clearly as dwarfs
(dCs), while ∼7% are giants. The dCs likely span absolute magnitudes
Mi from ∼6.5 to 10.5. "G-type" dC stars with weak CN and relatively
blue colors are probably the most massive dCs still cool enough to
show C2bands. We report Balmer emission in 22 dCs, none of which are
G-types. We find 8 new DA/dC stars in composite spectrum binaries,
quadrupling the total sample of these "smoking guns" for AGB binary
mass transfer. Eleven very red C stars with strong red CN bands appear
to be "N"-type AGB stars at large Galactocentric distances, one likely
a new discovery in the dIrr galaxy Leo A. Two such stars within 30' of
each other may trace a previously unidentified dwarf galaxy or tidal
stream at ∼40 kpc. We explore the multiwavelength properties of the
sample and report the first X-ray detection of a dC star, which shows
strong Balmer emission. Our own spectroscopic survey additionally
provides the dC surface density from a complete sample of dwarfs
limited by magnitude, color, and proper motion.
Description:
Using the 1.5m Tillinghast reflector and FAST spectrograph at the Fred
L. Whipple observatory on Mt Hopkins, we obtained FLWO1.5m/FAST
spectroscopy of dC candidates. From 2009 May until 2010 May, we
obtained 291 FAST spectra, spanning 3470-7400Å at 1.5Å/pixel
resolution. We find that 10 of these are bona fide new dC stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 127 1211 Carbon stars with SDSS spectroscopy
table3.dat 99 167 DQ white dwarfs with SDSS spectroscopy
table4.dat 101 10 Dwarf carbon stars confirmed with FAST spectroscopy
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2014)
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
II/312 : GALEX-DR5 (GR5) sources from AIS and MIS (Bianchi+ 2011)
II/306 : The SDSS Photometric Catalog, Release 8 (Adelman-McCarthy+, 2011)
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
III/227 : General Catalog of galactic Carbon stars, 3d Ed. (Alksnis+ 2001)
J/A+A/544/L6 : Images of two DQ white dwarfs (Vornanen+, 2012)
J/ApJ/714/663 : Stellar density map of the Milky Way (de Jong+, 2010)
J/ApJS/181/444 : X-emitting stars identified from RASS/SDSS (Agueros+, 2009)
J/ApJS/178/339 : ChaMP extended stellar survey (ChESS) (Covey+, 2008)
J/AJ/136/1921 : Variable stars of Draco dSph (Kinemuchi+, 2008)
J/AJ/134/2398 : Stellar SEDs in SDSS and 2MASS filters (Covey+, 2007)
J/AJ/134/2340 : Membership of Praesepe & Coma Berenices (Kraus+, 2007)
J/A+A/473/143 : RVs of C stars near Galactic plane (Demers+, 2007)
J/A+A/447/473 : R I CN TiO phot. of DDO190 carbon stars (Battinelli+, 2006)
J/A+A/436/91 : C star population in outer disk of M31 (Demers+, 2005)
J/ApJS/152/103 : Proper-motion catalog SDSS + USNO-B (Gould+, 2004)
J/AJ/127/2838 : Faint high-latitude C stars SDSS photometry (Downes+, 2004)
J/AJ/124/1651 : Faint high-latitude C stars SDSS photometry (Margon+, 2002)
J/AZh/76/604 : Spectrophotometry of S and carbon stars (Tereshchenko, 1999)
J/ApJS/105/419 : Spectral Atlas of Carbon Stars (Barnbaum+ 1996)
http://www.sdss.org/ : SDSS home page
Byte-by-byte Description of file: table[14].dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Name SDSSJ Name (G1)
20- 27 F8.2 d Epoch ? SDSS MJD of SDSS DR8 astrometry (G2)
29- 33 F5.2 mag rmag [7/24] SDSS dereddened r band PSF magnitude
35- 39 F5.2 mag u-g SDSS u-g color index
41- 44 F4.2 mag g-r SDSS g-r color index
46- 50 F5.2 mag r-i SDSS r-i color index
52- 56 F5.2 mag i-z SDSS i-z color index
58- 62 F5.2 mag J-H ? The J-H color index (1)
64- 69 F6.2 mag H-K ? The H-K color index (1)
71- 75 F5.2 mag r-J ? The r-J color index from SDSS vs. UKIDSS or
2MASS
77- 82 F6.1 mas/yr pmRA [-361/208]? Proper motion in Right Ascension
84- 88 F5.1 mas/yr e_pmRA ? The 1σ error in pmRA
90- 95 F6.1 mas/yr pmDE [-458/107]? Proper motion in Declination
97-101 F5.1 mas/yr e_pmDE ? The 1σ error in pmDE
102 A1 --- --- [0]
104-108 F5.2 mag NUV ? GALEX NUV magnitude
110-114 F5.2 mag FUV [16/26]? GALEX FUV magnitude
116-119 F4.2 mag iMag ? Absolute i band magnitude estimate (2)
121-125 A5 --- Class Note(s) on Luminosity Class (G3)
127 A1 --- D04 [1] 1 = in Downes et al. 2004 (J/AJ/127/2838)
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Note (1): Near-IR magnitudes taken from UKIDSS where available, then 2MASS PSC
Note (2): Absolute i-band magnitude calculated from r-i color as described in
the paper, assuming that the object is a main sequence star.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Name SDSSJ Name (G1)
20- 27 F8.2 d Epoch ? SDSS MJD of position from SDSS DR8 (G2)
29- 33 F5.2 mag rmag [15/22] SDSS dereddened r band PSF magnitude
35- 39 F5.2 mag u-g SDSS u-g color index
41- 45 F5.2 mag g-r SDSS g-r color index
47- 51 F5.2 mag r-i SDSS r-i color index
53- 57 F5.2 mag i-z SDSS i-z color index
59- 63 F5.2 mag NUV ? GALEX NUV magnitude
65- 69 F5.2 mag FUV [18.6/24.5]? GALEX FUV magnitude
71- 77 F7.1 mas/yr pmRA [-1025/179]? Proper motion in Right Ascension
79- 82 F4.1 mas/yr e_pmRA ? The 1σ error in pmRA
84- 90 F7.1 mas/yr pmDE [-1465/347]? Proper motion in Declination
92- 95 F4.1 mas/yr e_pmDE ? The 1σ error in pmDE
97- 99 A3 --- Notes Note(s) on spectral features (G3)
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Global notes:
Note (G1): Coordinate names are truncated rather than rounded;
precise astrometry is available in the SDSS archive.
Note (G2): Epoch in Modified Julian Day provided only for those objects with
significant proper motions as described in the text.
Note (G3): Luminosity classes (lower case) and spectral classes notes
(upper case) as follows:
d = Dwarf;
g = Giant;
u = Uncertain;
n = No proper motion data.
G = "G-type carbon star";
E = emission lines;
L = low S/N spectrum;
N = likely N-type (extremely red, usually strong CN);
T = candidate extragalactic object;
X = X-ray source;
R = in Draco dwarf galaxy (Draco C-1).
C = unusual continuum shape and/or possible composite;
M = detected in 2MASS;
P = deep molecular bandheads;
W = weak molecular bandheads.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 29-Oct-2014