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J/A+A/583/A86       DB white dwarfs in SDSS DR10 and DR12    (Koester+, 2015)

DB white dwarfs in the Sloan Digital Sky Survey Data Release 10 and 12. Koester D., Kepler S.O. <Astron. Astrophys. 583, A86 (2015)> =2015A&A...583A..86K (SIMBAD/NED BibCode)
ADC_Keywords: Stars, white dwarf ; Abundances Keywords: white dwarf - stars: atmosphere - stars: abundances - convection - accretion, accretion disks Abstract: White dwarfs with helium-dominated atmospheres (spectral types DO, DB) comprise approximately 20% of all white dwarfs. There are fewer studies than of their hydrogen-rich counterparts (DA) and thus several questions remain open. Among these are the total masses and the origin of the hydrogen traces observed in a large number and the nature of the deficit of DBs in the range from 30000-45000K. We use the largest-ever sample (by a factor of 10) provided by the Sloan Digital Sky Survey (SDSS) to study these questions. The photometric and spectroscopic data of 1107 helium-rich objects from the SDSS are analyzed using theoretical model atmospheres. Along with the effective temperature and surface gravity, we also determine hydrogen and calcium abundances or upper limits for all objects. The atmosphere models are extended with envelope calculations to determine the extent of the helium convection zones and thus the total amount of hydrogen and calcium present. Description: Stellar parameters for the DB white dwarfs in the SDSS Data Release 10 and 12: effective temperature, surface gravity, signal-to-noise ratio, distance, distance above galactic plane, logarithmic abundances of H and Ca. A zero value for the errors means that the surface gravity was kept fixed at 8.00, or for the abundances that these are upper limits. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 83 1107 DB stellar parameters
See also: J/MNRAS/446/4078 : New white dwarf stars in SDSS DR10 (Kepler+, 2015) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 19 A19 --- Name SDSS name, 22- 26 I5 K Teff Effective temperature 28- 30 I3 K e_Teff Error of effective temperature 33- 37 F5.3 [cm/s2] logg log of surface gravity in cgs units 39- 43 F5.3 [cm/s2] e_logg Error of surface gravity 46- 49 F4.1 --- S/N Signal-to-noise ratio of spectrum 52- 54 I3 pc d Distance 57- 59 I3 pc Z Vertical height above galactic plane 62- 66 F5.2 [-] [H/He] Hydrogen abundances log N(H)/N(He) 68- 71 F4.2 [-] e_[H/He] Error of hydrogen abundance 73- 78 F6.2 [-] [Ca/He] Calcium abundance log N(Ca)/N(He) 80- 83 F4.2 [-] e_[Ca/He] Error of calcium abundance
Acknowledgements: Detlev Koester, koester(at) History: * 30-Oct-2015: First on-line version * 31-Oct-2015: correction of 015904.10+144151.04 name * 02-Nov-2015: correction of 111203.60+215747.42 name
(End) D. Koester [Univ. of Kiel, Germany], P. Vannier [CDS] 03-Sep-2015
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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