1. The dynamical mass of a classical Cepheid variable star in an eclipsing binary system.
- Author
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Pietrzyński, G., Thompson, I. B., Gieren, W., Graczyk, D., Bono, G., Udalski, A., Soszyński, I., Minniti, D., and Pilecki, B.
- Subjects
STARS ,BINARY stars ,STELLAR oscillations ,CEPHEIDS ,COMPACT objects (Astronomy) ,ASTRONOMY ,ECLIPSES ,STELLAR structure - Abstract
Stellar pulsation theory provides a means of determining the masses of pulsating classical Cepheid supergiants-it is the pulsation that causes their luminosity to vary. Such pulsational masses are found to be smaller than the masses derived from stellar evolution theory: this is the Cepheid mass discrepancy problem, for which a solution is missing. An independent, accurate dynamical mass determination for a classical Cepheid variable star (as opposed to type-II Cepheids, low-mass stars with a very different evolutionary history) in a binary system is needed in order to determine which is correct. The accuracy of previous efforts to establish a dynamical Cepheid mass from Galactic single-lined non-eclipsing binaries was typically about 15-30% (refs 6, 7), which is not good enough to resolve the mass discrepancy problem. In spite of many observational efforts, no firm detection of a classical Cepheid in an eclipsing double-lined binary has hitherto been reported. Here we report the discovery of a classical Cepheid in a well detached, double-lined eclipsing binary in the Large Magellanic Cloud. We determine the mass to a precision of 1% and show that it agrees with its pulsation mass, providing strong evidence that pulsation theory correctly and precisely predicts the masses of classical Cepheids. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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