The Orbital and Physical Properties of Five Southern Be+sdO Binary Systems

Close binary interactions may play a critical role in the formation of the rapidly rotating Be stars. Mass transfer can result in a mass gainer star spun up by the accretion of mass and angular momentum, while the mass donor is stripped of its envelope to form a hot and faint helium star. Far-UV spe...

Full description

Saved in:
Bibliographic Details
Published in:The Astronomical journal 2023-05, Vol.165 (5), p.203
Main Authors: Wang, Luqian, Gies, Douglas R., Peters, Geraldine J., Han, Zhanwen
Format: Article
Language:English
Subjects:
Algorithms
Angular momentum
Astronomy
B stars
Binary systems
Companion stars
Deposition
Emission line stars
Helium
Mass ratios
Mass transfer
Orbits
Physical properties
Spectroscopic binary stars
Spectroscopy
Spectrum analysis
Stars
Stellar evolution
Stellar rotation
Supernovae
Ultraviolet spectroscopy
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Close binary interactions may play a critical role in the formation of the rapidly rotating Be stars. Mass transfer can result in a mass gainer star spun up by the accretion of mass and angular momentum, while the mass donor is stripped of its envelope to form a hot and faint helium star. Far-UV spectroscopy has led to the detection of about 20 such binary Be+sdO systems. Here we report on a 3 yr program of high-quality spectroscopy designed to determine the orbital periods and physical properties of five Be binary systems. These binaries are long orbital period systems with P = 95–237 days and small semiamplitude K 1 < 11 km s −1 . We combined the Be star velocities with prior sdO measurements to obtain mass ratios. A Doppler tomography algorithm shows the presence of the He ii λ 4686 line in the faint spectrum of the hot companion in four of the targets. We discuss the observed line variability and show evidence of phase-locked variations in the emission profiles of HD 157832, suggesting a possible disk spiral density wave due to the presence of the companion star. The stripped companions in HD 113120 and HD 137387 may have a mass larger than 1.4 M ⊙ , indicating that they could be progenitors of Type Ib and Ic supernovae.
ISSN:0004-6256
1538-3881
DOI:10.3847/1538-3881/acc6ca