THE ORBITAL AND PHYSICAL PARAMETERS, AND THE DISTANCE OF THE ECLIPSING BINARY SYSTEM OGLE-LMC-ECL-25658 IN THE LARGE MAGELLANIC CLOUD
- Universidad de Concepción, Departamento de Astronomia, Casilla 160-C, Concepción (Chile)
- Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 911101-1292 (United States)
- Warsaw University Observatory, Al. Ujazdowskie 4, PL-00-478, Warszawa (Poland)
- Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, ul. Bartycka 18, 00-716 Warszawa (Poland)
We present an analysis of a new detached eclipsing binary, OGLE-LMC-ECL-25658, in the Large Magellanic Cloud (LMC). The system consists of two late G-type giant stars on an eccentric orbit with an orbital period of ∼200 days. The system shows total eclipses and the components have similar temperatures, making it ideal for a precise distance determination. Using multi-color photometric and high resolution spectroscopic data, we have performed an analysis of light and radial velocity curves simultaneously using the Wilson–Devinney code. We derived orbital and physical parameters of the binary with a high precision of <1%. The masses and surface metallicities of the components are virtually the same and equal to 2.23±0.02 M{sub ⊙} and [Fe/H] = −0.63±0.10 dex. However, their radii and rates of rotation show a distinct trace of differential stellar evolution. The distance to the system was calculated using an infrared calibration between V-band surface brightness and (V–K) color, leading to a distance modulus of (m−M) = 18.452±0.023 (statistical) ± 0.046 (systematic). Because OGLE-LMC-ECL-25658 is located relatively far from the LMC barycenter, we applied a geometrical correction for its position in the LMC disk using the van der Marel et al. model of the LMC. The resulting barycenter distance to the galaxy is d{sub LMC} = 50.30±0.53 (stat.) kpc, and is in perfect agreement with the earlier result of Pietrzyński et al.
- OSTI ID:
- 22862908
- Journal Information:
- The Astronomical Journal (Online), Vol. 152, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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