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| Paper: |
Variability in the Milky Way: Contact Binaries as Diagnostic Tools |
| Volume: |
511, Non-Stable Universe: Energetic Resources, Activity Phenomena and Evolutionary Processes |
| Page: |
23 |
| Authors: |
de Grijs, R.; Chen, X.; Deng, L. |
| Abstract: |
We used the 50 cm Binocular Network (50BiN) telescope at Delingha
Station (Qinghai Province) of Purple Mountain Observatory (Chinese
Academy of Sciences) to obtain simultaneous V- and R-band
observations of the old open cluster NGC 188. Our aim was a search for
populations of variable stars. We derived light-curve solutions for
six W Ursae Majoris (W UMa) eclipsing-binary systems and estimated
their orbital parameters. The resulting distance to the W UMas is
independent of the physical characteristics of the host cluster. We
next determined the current best period–luminosity relations for
contact binaries (CBs; scatter σ<0.10 mag). We conclude that
CBs can be used as distance tracers with better than 5%
uncertainty. We apply our new relations to the 102 CBs in the Large
Magellanic Cloud, which yields a distance modulus of
(m–M)V,0=18.41±0.20 mag. |
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