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2004MNRAS.347..173S - Mon. Not. R. Astron. Soc., 347, 173-186 (2004/January-1)
Continuous and burst-like accretion on to substellar companions in Mira winds.
STRUCK C., COHANIM B.E. and WILLSON L.A.
Abstract (from CDS):
The character of the accretion on to the companion changes greatly as the companion mass is increased. At the lowest companion masses considered here, a low continuous rate of mass accretion is punctuated by large, nearly periodic bursts of accretion. When the companion mass is large, the mass accretion has both a continuous part and a rapidly varying, nearly stochastic part. Surprisingly, the angular momentum of the accreted gas shows an opposite trend with mass, varying nearly periodically at large companion masses and stochastically at low masses. These trends can be understood as the result of the interplay between the shocks and radial oscillations in the circumstellar gas and the wake flow behind the companion. Boundary conditions also affect the character of the accretion. The equation of state, however, is found to have little effect, at least for gamma-law gases, with gamma in the range from 1 to 5/3.
Models with accretion bursts may produce observable optical brightenings, and may affect SiO maser emission, as we suggested in previous papers. Interruptions of continuous accretion, or shadowing effects, could give rise to bursts of dimming in the optical. Such dimming effects are likely to be correlated with bursts and optical flashes, helping to explain some rather mysterious Hipparcos observations.
Abstract Copyright: 2004 RAS
Journal keyword(s): accretion, accretion discs - masers - stars: AGB and post-AGB - circumstellar matter - planetary systems - stars: winds, outflows
Simbad objects: 5
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