The effects of unresolved binary stars on the determination of the stellar mass function.
Abstract
The effect of unresolved binary stars on the stellar luminosity function that results from a given mass function is quantified. It is such that previous studies have significantly underestimated the numbers of lowmass stars. Assuming that both component masses of a binary system are chosen independently from the same mass function, unresolved binary systems can account for the difference between the shapes of those luminosity functions deduced from photographic samples and that deduced from nearby stars with trigonometric parallaxes. The best results are obtained if all stars are binary systems with two hydrogenburning components. A mass function composed of two powerlaw segments represents a good solution if its index decreases appreciably below about half a solar mass. When extrapolated to zero mass this mass function contributes at most 20 per cent to the Oort limit. The minimum number of binary systems consistent with both luminosity functions lies between 43 and 56 per cent of stellar objects.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 July 1991
 DOI:
 10.1093/mnras/251.2.293
 Bibcode:
 1991MNRAS.251..293K
 Keywords:

 Astronomical Photometry;
 Binary Stars;
 Stellar Luminosity;
 Stellar Mass;
 Brown Dwarf Stars;
 Galactic Structure;
 HertzsprungRussell Diagram;
 Monte Carlo Method;
 Stellar Magnitude;
 Astrophysics