J/ApJ/663/1291 DZ stars in SDSS DR4 (Dufour+, 2007)
On the spectral evolution of cool, helium-atmosphere white dwarfs:
detailed spectroscopic and photometric analysis of DZ stars.
Dufour P., Bergeron P., Liebert J., Harris H.C., Knapp G.R., Anderson S.F.,
Hall P.B., Strauss M.A., Collinge M.J., Edwards M.C.
<Astrophys. J., 663, 1291-1308 (2007)>
=2007ApJ...663.1291D 2007ApJ...663.1291D
ADC_Keywords: Stars, white dwarf ; Effective temperatures ; Abundances
Keywords: stars: abundances - stars: atmospheres - stars: evolution -
white dwarfs
Abstract:
We present a detailed analysis of a large spectroscopic and
photometric sample of DZ white dwarfs based on our latest model
atmosphere calculations. We revise the atmospheric parameters of the
trigonometric parallax sample of Bergeron, Leggett, & Ruiz (2001,
Cat. J/ApJS/133/413, 12 stars) and analyze 147 new DZ white dwarfs
discovered in the SDSS. The inclusion of metals and hydrogen in our
model atmosphere calculations leads to different atmospheric
parameters than those derived from pure helium models.
Description:
The first sample used for this study is drawn from the Bergeron et al.
(1997ApJS..108..339B 1997ApJS..108..339B, BRL97) and (2001, Cat. J/ApJS/133/413, BLR01)
analyses, which include 12 DZ stars with optical BVRI and infrared JHK
photometry, as well as trigonometric parallax measurements, with the
exception of ESO 445-271 (WD 1338-311), for which the parallax and JHK
measurements are not available.
Our second sample consists of DZ white dwarfs spectroscopically
identified in the SDSS. We selected all DZ stars from the First and
Fourth Data Release white dwarf catalogs (Kleinman et al. 2004, Cat.
J/ApJ/607/426 and Eisenstein et al. 2006, Cat. J/ApJS/167/40).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 78 147 Atmospheric parameters of DZ Stars from the SDSS
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See also:
J/ApJ/607/426 : Catalog of white dwarfs in SDSS-DR1 (Kleinman+, 2004)
J/ApJS/167/40 : SDSS4 confirmed white dwarfs catalog (Eisenstein+, 2006)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS SDSS designation (JHHMMSS.ss+DDMMSS.s)
26- 29 I4 --- Plate SDSS plate number
31- 35 I5 --- MJD SDSS MJD number
37- 39 I3 --- Fiber SDSS Fiber number
41- 45 I5 K Teff Effective temperature
47- 49 I3 K e_Teff rms uncertainty on Teff
51- 56 F6.2 [-] log(Ca/He) Ca/He abundance
58- 61 F4.2 [-] e_log(Ca/He) rms uncertainty on log(Ca/He)
63- 65 I3 pc Dist Heliocentric distance
67 A1 --- l_log(H/He) Limit flag on log(H/He)
68- 72 F5.2 [-] log(H/He) H/He abundance
74- 77 F4.2 [-] e_log(H/He) ? rms uncertainty on log(H/He)
78 A1 --- R [*] indicates the SDSS name was corrected at
CDS (see the "History" section below)
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History:
* 19-Aug-2009: From electronic version of the journal
* 20-Jan-2010: 4 errors detected in the sign of the SDSS designation
and fixed at CDS; these records are marked by an asterisk (*)
in the additional column "R" of the table (Fabienne Woelfel, CDS)
(End) Patricia Vannier [CDS] 19-Aug-2009