Dynamical mass of a Cepheid again

Very precise mass determination of the Cepheid OGLE-LMC-CEP-1812 in an eclipsing binary system.

The Araucaria Project: Accurate Determination of the Dynamical Mass of the Classical Cepheid in the Eclipsing System OGLE-LMC-CEP-1812

G. Pietrzyński, I. Thompson, D. Graczyk, W. Gieren, B. Pilecki, A. Udalski, I. Soszynski, G. Bono, P. Konorski, N. Nardetto, J. Storm

2011, ApJ, 742, L20

Radial velocity curve of the system OGLE-LM-CEP-1812

After the first dynamical mass determination of the Cepheid in eclipsing binary OGLE-LMC-CEP-0227, the second successful mass determination has been made. An eclipsing binary system OGLE-LMC-CEP-1812 consists of a classical fundamental mode Cepheid pulsating with a period of 1.31 days and a mass of 3.74 ± 0.06 M, and a stable giant with a mass of 2.64 ± 0.04 M. The dynamical masses for both stars were derived with an accuracy of 1.5% and agree very well with that predicted by pulsation models. This new, very accurate dynamical mass for a classical Cepheid will greatly contribute to the solution of the Cepheid mass discrepancy problem, and to our understanding of the structure and evolution of classical Cepheids.

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