Abel investigated the binary system ϕ Persei, using new data by Douglas Gies and collaborators. The system contains one star, a subdwarf, with about the same mass as the Sun, but it is 10 times hotter and nearly 10,000 times brighter. It contains a second star, a Be star, that is nearly 10 times as massive as the Sun, which is spinning very rapidly. It is thought that the hot star is the remaining core of a star that has lost its envelope, transferring part of it to the companion which is now spinning very fast.
A. Schootemeijer, Y. Gotberg, S. E. de Mink, D. R. Gies, E. Zapartas, Clues about the scarcity of stripped-envelope stars from the evolutionary state of the sdO+Be binary system phi Persei, accepted for publication in A&A, 2018 https://arxiv.org/abs/1803.02379 Continue reading