Synthetic Colors and Evolutionary Sequences of Hydrogen- and Helium-Atmosphere White Dwarfs

Pierre Bergeron, Gilles Fontaine
Département de physique
Université de Montréal,

Pier-Emmanuel Tremblay
University of Warwick

Piotr M. Kowalski
Forschungszentrum Juelich GmbH

Sirius B

Synthetic Colors

Tables are provided with bolometric and absolute magnitudes on various photometric systems, which include the Johnson-Kron-Cousins UBVRI, the Stromgren uvby filters, the 2MASS JHKs, the Sloan Digital Sky Survey ugriz filters, and the mutlichannel color indices, 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 (2006, AJ, 132, 1221, "Calibration of Synthetic Photometry Using DA White Dwarfs"), which represent an extension of the earlier work by Bergeron, Wesemael, & Beauchamp (1995, PASP, 107, 1047, "Photometric Calibration of Hydrogen-and Helium-Rich White Dwarf Models"). For each set of filters, the files Table_DA and Table_DB correspond to pure hydrogen and pure helium atmosphere models, respectively. The DA model grid covers a range from Teff = 1500 K to 100,000 K and from log g = 7.0 to 9.0 (see Tremblay, Bergeron, & Gianninas 2011, ApJ, 730, 128 and references therein) and include the Lyman alpha profile calculations from Kowalski & Saumon (2006, ApJ, 651, L137). The DB model grid covers a range from Teff = 3500 K to 40,000 K and from log g = 7.0 to 9.0 (see Bergeron et al. 2011, ApJ, 737, 28 and references therein). Calculations are also provided for both DA and DB models but at a given mass.


If you are using any of these color tables, please acknowledge this Web site ( and include the following references for the color and model calculations: Holberg & Bergeron (2006, AJ, 132, 1221), Kowalski & Saumon (2006, ApJ, 651, L137), Tremblay et al. (2011, ApJ, 730, 128), and Bergeron et al. (2011, ApJ, 737, 28).

Last update : October 23rd, 2016.





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 Msun, etc. These sequences are similar except for the value of the total mass (21 values between 0.2 and 1.3 Msun). 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 Msun, etc. There are 16 different values of the total mass, again between 0.2 and 1.3 Msun.

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.

C_0200204 CO_0200204 CO_0200210
C_0300204 CO_0300204 CO_0300210
C_0400204 CO_0400204 CO_0400210
C_0450204 CO_0500204 CO_0500210
C_0500204 CO_0600204 CO_0600210
C_0550204 CO_0700204 CO_0700210
C_0600204 CO_0800204 CO_0800210
C_0650204 CO_0900204 CO_0900210
C_0700204 CO_0950204 CO_0950210
C_0750204 CO_1000204 CO_1000210
C_0800204 CO_1050204 CO_1050210
C_0850204 CO_1100204 CO_1100210
C_0900204 CO_1150204 CO_1150210
C_0950204 CO_1200204 CO_1200210
C_1000204 CO_1250204 CO_1250210
C_1050204 CO_1300204 CO_1300210