Helium-rich hot subdwarfs and single low-mass white dwarfs: Formation mechanisms and further implications
Date
2010
Authors
Justham, Stephen
Podsiadlowski, Ph.
Han, Zhanwen
Wolf, Christian
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Publisher
Kluwer Academic Publishers
Abstract
Variations in the mass loss from single stars have been used to explain the existence of hot subdwarf stars and the existence of single low-mass white dwarfs (LMWDs). Hence remaining uncertainty in mass loss from single red-giant stars is important to the understanding of these problems. However, natural formation channels for hot subdwarfs and single LMWDs have also been proposed which do not rely on unexplained mass loss from single red-giant stars. We outline these, and discuss how the different mechanisms could be distinguished. For example, a formation channel for single LMWDs which involves the break-up of a binary system by a type Ia supernova should produce a population of single LMWDs with a distinct kinematic signature. If that population is found to exist, it could be used to study one of the popular single-degenerate formation channels for type Ia supernovae in a previously impossible way. In addition, we examine the formation of helium-rich sdO stars-which are shown to emerge from one of the previously existing binary formation channels for hot subdwarfs. Both the SN Ia formation mechanism for single LMWDs and the formation channel for He-sdOs are a natural consequence of existing models. Hence if these formation channels do not work at all, then the result is a significant one.
Description
Keywords
Keywords: Binaries: close; Subdwarfs; Supernovae; White dwarfs
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Source
Astrophysics and Space Science
Type
Journal article
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2037-12-31