White Dwarf Primary Spectrophotometric Standards

A group headed by R. Bohlin at STScI have establisheda set of four white dwarf standards based on comparison of White Dwarf model atmospheres with HST FOS spectra. They aredescribed in Bohlin, Colina & Finlay, AJ, 110, 1316, 1995.The wavelength coverage is 10A to 3 microns. Extension of the white dwarf primary standards to more stars, giving 27 in total, are described in Bohlin (Proceedings of STScI HST Calibration Workshop, eds. A. Koratkar & C. Leitherer, p. 49, 1994) and in Bohlin (AJ, 111, 1743, 1996).

The hydrogen white dwarfs (see list below) cover a widerange in effective temperature and the FOS spectrophotometry agreeswith the model fluxes to within 2% over the whole UV-visible range.In addition, the simulated B and V magnitudes of the data agree to better than 1% with Landolt photometry. Bohlin et al. (1995)recommend these four White Dwarf standards as primary reference standards for all UV and optical calibrations from 1000 to >10000A.

The data are stored as flux values (ergs/cm/cm/s/A). They have also been converted to ABMAG using the formula
ABMAG = -2.5 alog10(Fnu) - 48.59
(Hamuy et al., PASP, 104, 533, 1992), where Fnu is in ergs/cm/cm/s/Hz.

 

                     WD Primary Standard Stars

Star RA (J2000) Dec B-V V Type Teff Log g
d m s d ' '' (K)
-------------------------------------------------------------------
G191-B2B 05 05 30.6 +52 49 54 -0.326 11.781 DA0 61300 7.50
GD 71 05 52 27.5 +15 53 17 -0.249 13.032 DA1 32300 7.73
GD 153 12 57 02.4 +22 01 56 -0.286 13.346 DA1 38500 7.67
HZ 43 13 16 22.0 +29 05 57 -0.302 12.914 DA1 50000 8.00