Accurate dynamical mass determination of a classical Cepheid in an eclipsing binary system

Understand

Stellar pulsation theory provides a means of determining the masses of pulsating classical Cepheid supergiant - 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 noneclipsing binaries was typically about 15-30 per cent, which is not good enough to resolve the mass discrepancy problem.