Absolute Dimensions of Contact Binary Stars in Baade Window

• Main Author: Young Woon Kang
• Format: Article
• Language: English
• Published: Korean Space Science Society (KSSS) 1999-12-01
• Series: Journal of Astronomy and Space Sciences
• Online Access: http://ocean.kisti.re.kr/downfile/volume/kosss/OJOOBS/1999/v16n2/OJOOBS_1999_v16n2_217.pdf

The light curves of the representative 6 contact binary stars observed by OGLE Project of searching for dark matter in our Galaxy have been analyzed by the method of the Wilson and Devinney Differential Correction to find photometric solutions. The orbital inclinations of these binaries are in the range of 52 deg - 69 deg which is lower than that of the solar neighborhood binaries. The Roche lobe filling factor of these binaries are distributed in large range of 0.12 - 0.90. Since absence of spectroscopic observations for these binaries we have found masses of the 6 binary systems based on the intersection between Kepler locus and locus derived from Vandenberg isochrones in the mass - luminosity plane. Then absolute dimensions and distances have been found by combining the masses and the photometric solutions. The distances of the 6 binary systems are distributed in the range of 1 kpc - 6 kpc. This distance range is the limiting range where the contact binaries which have period shorter than a day are visible. Most contact binaries discovered in the Baade window do not belong to the Galactic bulge.