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. =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 M_i_ 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 C_2_bands. 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 3470-7400{AA} at 1.5{AA}/pixel resolution. We find that 10 of these are bona fide new dC stars. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- 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 -------------------------------------------------------------------------------- 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 -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 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 1{sigma} 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 1{sigma} 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) -------------------------------------------------------------------------------- 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. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 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 1{sigma} 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 1{sigma} error in pmDE 97- 99 A3 --- Notes Note(s) on spectral features (G3) -------------------------------------------------------------------------------- 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. -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 29-Oct-2014