
Eclipsing binaries in open clusters – III. V621 Per in χ Persei
Author(s) -
Southworth J.,
Zucker S.,
Maxted P. F. L.,
Smalley B.
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.08389.x
Subject(s) - physics , astrophysics , balmer series , radius , open cluster , binary star , stars , surface gravity , radial velocity , star cluster , light curve , primary (astronomy) , diagram , stellar mass , astronomy , emission spectrum , star formation , spectral line , statistics , computer security , mathematics , computer science
V621 Persei is a detached eclipsing binary in the open cluster χ Persei, which is composed of an early B‐type giant star and a main‐sequence secondary component. From high‐resolution spectroscopic observations and radial velocities from the literature, we determine the orbital period to be 25.5 d and the primary velocity semi‐amplitude to be K = 64.5 ± 0.4 km s −1 . No trace of the secondary star has been found in the spectrum. We solve the discovery light curves of this totally eclipsing binary and find that the surface gravity of the secondary star is log g B = 4.244 ± 0.054 . We compare the absolute masses and radii of the two stars in the mass–radius diagram, for different possible values of the primary surface gravity, with the predictions of stellar models. We find that log g A ≈ 3.55 , in agreement with values found from fitting Balmer lines with synthetic profiles. The expected masses of the two stars are 12 and 6 M ⊙ and the expected radii are 10 and 3 R ⊙ . The primary component is near the blue loop stage in its evolution.