2010, Nature, 468, 542-544 (← click to see the publication at ADS/arXiv)
The two ways to determine the Cepheid mass – from stellar pulsation theory and from stellar evolution theory – yield the results different by 30% (the Cepheid mass discrepancy problem). The accuracy of previous efforts to establish a dynamical Cepheid mass from single-lined non-eclipsing binaries was ∼ 15−30%, not good enough to resolve the mass discrepancy problem. The discovery of a classical Cepheid OGLE-LMC-CEP0227 in a well detached, double-lined eclipsing binary allowed to determine the mass of the pulsator to 4.14 M☉ with a precision of 1.2%. This determination agrees with its pulsation mass, providing strong evidence that pulsation theory correctly and precisely predicts the masses of classical Cepheids.