HD 50975: a yellow supergiant in a spectroscopic binary system

Context. Recent detection of a yellow supergiant star as a possible progenitor of a supernova has posed serious questions about our understanding of the evolution of massive stars. Aims. The spectroscopic binary star HD 50975 with an unseen hot secondary was studied in detail with the main goal of estimating fundamental parameters of both components and the binary system. Methods. A comprehensive analysis and modeling of collected long-term radial velocity measurements, photometric data, and spectra was performed to calculate orbital elements, atmospheric parameters, abundances, and luminosities. The spectrum in an ultraviolet region was studied to clarify the nature of an unseen companion …