Year: 1998
Type: article
Abstract: We consider the formation of low-mass X-ray binaries (LMXBs) containing accreting neutron stars via the helium star supernova channel. The predicted relative number of short-period transients provides a sensitive test of the input physics in this process. We investigate the effect of varying mean kick velocities, orbital angular momentum loss efficiencies, and common-envelope ejection efficiencies on the subpopulation of short-period systems, both transient and persistent. Guided by the thermal-viscous disk instability model in irradiation-dominated disks, we posit that short-period transients have donors close to the end of core hydrogen burning. We find that with increasing mean kick velocity the overall short-period fraction, s , grows, while the fraction r of systems with evolved donors among short-period systems drops. This effect, acting in opposite directions on these two fractions, allows us to constrain models of LMXB formation through comparison with observational estimates of s and r . Without fine tuning or extreme assumptions about evolutionary parameters, consistency between models and current observations is achieved for a regime of intermediate average kick magnitudes of about 100-200 km s -1 , provided that (1) orbital braking for systems with donor masses in the range 1-1.5 M ☉ is weak, i.e., much less effective than a simple extrapolation of standard magnetic braking beyond 1.0 M ☉ would suggest, and (2) the efficiency of common-envelope ejection is low.
Source: The Astrophysical Journal
DOI: 10.1086/306119
Authors: V. Kalogera, U. Kolb, A. R. King
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2015716217