Synthetic Colors and Evolutionary Sequences of Hydrogen- and Helium-Atmosphere White Dwarfs
Pierre Bergeron & Gilles FontaineDépartement de physique
Université de Montréal
bergeron@astro.umontreal.ca
Synthetic Colors
Tables are provided with bolometric and absolute magnitudes on various photometric systems which include the Johnson-Kron-Cousins UBVRI, the Strömgren uvby filters, the 2MASS JHKs and the Sloan Digital Sky Survey ugriz filters for an extensive grid of hydrogen- and helium-rich white dwarf model atmospheres. These calculations can easily be extended to any given photometric system upon request.
Stellar masses and cooling ages are also obtained for each model from detailed evolutionary cooling sequences appropriate for these stars. For the pure hydrogen model atmospheres above Teff = 30,000 K, we use the carbon-core cooling models of Wood (1995, in 9th European Workshop on White Dwarfs, NATO ASI Series, eds. D. Koester & K. Werner, p. 41) with thick hydrogen layers of qH≡MH/M*=10–4, while for Teff below 30,000 K we rely on cooling models similar to those described in Fontaine, Brassard, & Bergeron (2001, PASP, 113, 409) but with carbon-oxygen cores and qH=10–4 (see Bergeron, Leggett, & Ruiz 2001, ApJS, 133, 413 for more details). For the pure helium model atmospheres we rely on similar models but with qH=10–10. The Fontaine et al. cooling sequences are provided below.
Details of the color calculations are given in Holberg & Bergeron "Calibration of Synthetic Photometry Using DA White Dwarfs" 2006, AJ, in press, and they represent an extension of the earlier work by Bergeron, Wesemael, & Beauchamp "Photometric Calibration of Hydrogen-and Helium-Rich White Dwarf Models" 1995, PASP, 107, 1047. For each set of filters, the files Table_DA and Table_DB correspond to pure hydrogen and pure helium atmosphere models, respectively. The DA grid covers a range from Teff = 1500 K to 100,000 K and from log g = 7.0 to 9.0, while the DB grid covers a range from Teff = 3500 K to 30,000 K and from log g = 7.0 to 9.0. Calculations are also provided for both DA and DB models but at a given mass.
| AllTables.tar.gz |
| Table_DA |
| Table_DB |
| Table_Mass_0.2 |
| Table_Mass_0.3 |
| Table_Mass_0.4 |
| Table_Mass_0.5 |
| Table_Mass_0.6 |
| Table_Mass_0.7 |
| Table_Mass_0.8 |
| Table_Mass_0.9 |
| Table_Mass_1.0 |
| Table_Mass_1.1 |
| Table_Mass_1.2 |
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Evolutionary Sequences
Three distinct families of evolutionary sequences are provided:
1) A set of 21 evolutionary sequences referring to pure C-core models
with standard "thick" H and He layers, i.e., with qH=10–4
and qHe=10–2. Hence the notation C_0200204 for the sequence
with M* = 0.2 M
, etc. These sequences are similar except for the
value of the total mass (21 values between 0.2 and 1.3 M). These
are the sequences published in Fontaine, Brassard, & Bergeron (2001, PASP, 113, 409).
2) A set of 16 evolutionary sequences for mixed C/O core composition
(50/50 by mass fraction mixed uniformly) and for standard "thick" H and
He layers. The notation is CO_0200204 for the sequence with M* = 0.2
M, etc. There are 16 different values of the total mass, again
between 0.2 and 1.3 M.
3) A similar set of 16 evolutionary sequences for mixed C/O core composition (50/50 by mass fraction mixed uniformly), but for "thin" H layers with qH=10–10 instead of 10–4.
The C_ files have headers that should be self-explanatory, while the CO_ files do not have such headers, but the format is identical to that of the C_ files. A sample header is provided in the file SampleHeader.
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