Sm. Rucinski, MV = MV(LOG-P, LOG TE) CALIBRATIONS FOR W-URSAE-MAJORIS SYSTEMS, Publications of the Astronomical Society of the Pacific, 106(699), 1994, pp. 462-471
Citations number
50
Categorie Soggetti
Astronomy & Astrophysics
Journal title
Publications of the Astronomical Society of the Pacific
We use the basic expression for luminosities of contact systems, L pro
portional-to area.T(e)4, to derive calibrations of their absolute magn
itudes M(V) in terms of the orbital period and color indices B-V and V
- I(C). These calibrations can serve as a consistency check on members
hip of W Ursae Majoris systems in stellar clusters and will permit the
use of W UMa binaries as distance indicators for stellar systems cons
isting of solar-type stars. The calibrating sample at this time is bas
ed on three systems with trigonometric parallaxes, eleven systems in h
igh galactic latitude open clusters, and three systems with main-seque
nce visual companions. The ranges in period and color are quite narrow
and the results must be considered as preliminary, especially for the
V-I(C) calibration. One of possible applications of the calibrations,
as a sieve to remove the foreground interlopers, is illustrated. The
result is that the cluster and field frequencies of optically detected
W UMa systems seem to be equal at about 1 per about 280 surveyed star
s (uncorrected for the inclination bias of about 2 times), which is ab
out 3-4 times higher in the field than estimated before.