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Astron. Astrophys. 338, 965-970 (1998)

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Wind-driven evolution of accreting binaries and the progenitors of SNe Ia

A.R. King 1, 2 and A. van Teeseling 1

1 Universitäts-Sternwarte Göttingen, Geismarlandstrasse 11, D-37083 Göttingen, Germany
2 Astronomy Group, University of Leicester, Leicester LE1 7RH, UK

Received 13 January 1998 / Accepted 6 August 1998


Strong self-excited winds from the companion are very likely in many accreting binaries, and we investigate their evolutionary effects. We show that in white dwarf systems with large mass ratios [FORMULA], self-excited winds naturally stabilize mass transfer at a threshold value [FORMULA] yr-1. Near this threshold value, irradiation-induced wind loss rates from the companion star become much higher, because of intermittent stable hydrogen shell burning on the accreting white dwarf. The white dwarf can accrete a substantial mass ([FORMULA]) during this evolution, and may produce a Type Ia supernova directly in some cases. In other cases the evolution may produce supersoft X-ray binaries with quite massive white dwarfs and moderate-mass companions, which then undergo thermal-timescale mass transfer and may produce SNe Ia themselves.

We show that the stability of such `bootstrap' evolution via a self-excited wind is indeterminate if the wind losses depend linearly on the mass transfer rate, as assumed in some analyses of low-mass X-ray binary evolution. Such analyses must be repeated with a more precise form of the wind-driving law. In practice systems with small mass ratios will tend to stabilize in regimes where the wind-driving law is slower than linear, with the opposite result for large mass ratios.

Key words: accretion, accretion disks – stars: mass-loss – novae, cataclysmic variables – supernovae: general – white dwarfs – X-rays: stars

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© European Southern Observatory (ESO) 1998

Online publication: September 17, 1998