Synthetic Colors

Tables are provided with bolometric and absolute magnitudes on various photometric systems for an extensive grid of pure-hydrogen and pure-helium white dwarf model atmospheres. These include, in this particular order, the Johnson-Kron-Cousins UBVRI, Two Micron All Sky Survey (2MASS) JHKs, Mauna Kea Observatory (MKO) YJHK, Wide-field Infrared Survey Explorer (WISE) W1 to W4, Spitzer Space Telescope Infrared Array Camera (IRAC) 3.6, 4.5, 5.8, and 8.0 microns, Sloan Digital Sky Survey (SDSS) ugriz, Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) grizy, Gaia G, G_BP, and G_RP, and Galaxy Evolution Explorer (Galex) FUV and NUV colors. 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. We use our latest generation of evolutionary sequences published in Bédard et al. (2020, ApJ, 901, 93) and provided below. We rely on stellar models with thick (q_H≡M_H/M_*=10^–4) and thin (q_H=10^–10) hydrogen layers for the pure-hydrogen and pure-helium model atmospheres, respectively.

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 model atmospheres, respectively. The DA grid covers a range from T_eff = 2500 K to 150,000 K and from log g = 7.0 to 9.0, while the DB grid covers a range from T_eff = 3250 K to 150,000 K and from log g = 7.0 to 9.0. At low temperatures (T_eff < 5000 K and 8000 K for the DA and DB grids, respectively), we use the models of Blouin et al. (2018, ApJ, 863, 184), which include non-ideal effects. At high temperatures (T_eff > 30,000 K and 40,000 K for the DA and DB grids, respectively), we rely on the models of Bédard et al. (2020, ApJ, 901, 93), which include non-LTE effects. At intermediate temperatures, we use the DA models of Tremblay, Bergeron, & Gianninas (2011, ApJ, 730, 128) and the DB models of Bergeron et al. (2011, ApJ, 737, 28). The DA grid incorporates the Lyman alpha profile calculations of Kowalski & Saumon (2006, ApJ, 651, L137). Tables are also provided at given masses for both DA and DB models through the files Table_Mass_*.

Acknowledgement: If you are using any of these color tables, please acknowledge this Web site (http://www.astro.umontreal.ca/~bergeron/CoolingModels) and include the relevant references mentioned above.

Last update: August 18th, 2020.

Evolutionary Sequences

The theoretical evolutionary sequences of Bédard et al. (2020, ApJ, 901, 93) are provided below. These calculations rely on white dwarf models characterized by a homogeneous and equimassic carbon/oxygen core, a helium mantle, and an outermost hydrogen layer. Two standard envelope compositions are considered, corresponding to a thick (q_He=10^–2, q_H=10^–4) and a thin (q_He=10^–2, q_H=10^–10) hydrogen layer. In each case, 23 cooling sequences covering a range from M_* = 0.2 M to 1.3 M are available. See Bédard et al. (2020) for details, including a discussion of the differences with respect to our previous generation of evolutionary sequences introduced by Fontaine, Brassard, & Bergeron (2001, PASP, 113, 409).

The name of a given file specifies the stellar mass and the thickness of the hydrogen layer: for instance, seq_060_thick refers to M_* = 0.6 M and q_H=10^–4. For each stellar model, we give, in this particular order, the effective temperature, surface gravity, radius, cooling age, photon luminosity, central temperature, central pressure, central density, fraction of crystallized mass, location of the crystallization front, neutrino luminosity, and total mass fractions of hydrogen, helium, carbon, and oxygen. We use cgs units throughout, and the header indicates which quantities are expressed as logarithms.

AllSequences.tar.gz

seq_020_thick	seq_020_thin
seq_025_thick	seq_025_thin
seq_030_thick	seq_030_thin
seq_035_thick	seq_035_thin
seq_040_thick	seq_040_thin
seq_045_thick	seq_045_thin
seq_050_thick	seq_050_thin
seq_055_thick	seq_055_thin
seq_060_thick	seq_060_thin
seq_065_thick	seq_065_thin
seq_070_thick	seq_070_thin
seq_075_thick	seq_075_thin
seq_080_thick	seq_080_thin
seq_085_thick	seq_085_thin
seq_090_thick	seq_090_thin
seq_095_thick	seq_095_thin
seq_100_thick	seq_100_thin
seq_105_thick	seq_105_thin
seq_110_thick	seq_110_thin
seq_115_thick	seq_115_thin
seq_120_thick	seq_120_thin
seq_125_thick	seq_125_thin
seq_130_thick	seq_130_thin