Revealing a numerous population of double-lined binary Cepheids

Bogumił Pilecki

Masses of classical Cepheids of 3 to 11M_☉ are predicted by theory but those measured clump between 3.6 to 5M_☉. As a result, their mass-luminosity relation is poorly constrained, impeding our understanding of basic stellar physics and the Leavitt Law. Here we present and summarize the first results of the project to study a new, numerous group of Cepheids in double-lined binary (SB2) systems with the aim to provide their mass determinations in a wide mass interval and learn about their evolution. We analyzed a sample of 41 candidates binary LMC Cepheids spread along the P-L relation and presented evidence that they are in majority accompanied by luminous red giants. In a spectroscopic study of a subsample of 18 brightest candidates, for 17 we detected lines of two components in the spectra, already quadrupling the number of Cepheids in SB2 systems.

Proceedings of the Polish Astronomical Society, vol. 12, 174-178 (2022)

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