Cousins BVRI photometry is presented for a sample of 100 hot, hydrogen-rich subdwarf candidates selected principally from the Palomar-Green (PG) and Kitt Peak-Downes colorimetric surveys. The combination of these data with existing Stroemgren photometry permits the construction of energy distributions in the range lambda lambda 3500-7900. With the help of flux-ratio diagrams, we have isolated 31 objects with flat energy distributions indicative of a composite nature. Approximate effective temperatures and spectral types are derived for the primary and secondary stars, respectively. We present evidence, based on the absolute visual magnitudes determined for the primary components, that the secondary stars in most systems are likely to be overluminous compared to normal main-sequence stars. Because of selection effects, the spectral types of the secondary stars are restricted to the range late G to early M. When allowance is made for these selection effects, the fraction of hot hydrogen-rich subdwarfs with main-sequence companions in the PG survey can be inferred, and is estimated to be approximately 54%-66%.
No takes yet. Share an insight, caveat, or question.
Allard et al. (1994) studied this question.