Does the Mass Accretion Rate Depend On the Radius of the Accreting Star?

Abraham Loeb; Ramesh Narayan; John Raymond

doi:10.1086/318913

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Does the Mass Accretion Rate Depend On the Radius of the Accreting Star?

Abraham Loeb·Ramesh Narayan·John Raymond

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Abstract

In some circumstances, the mass accretion rate M^dot onto a compact star may depend not only on external boundary conditions, but also on the radius R of the star. Writing the dependence as a power-law in which M^dot is proportional to R^p, we estimate the power-law index, p, for transient binary systems in a quiescent state. We use the observed luminosities $L$ of accreting neutron stars (R=10^6 cm) in soft X-ray transients and white dwarfs (R=10^9 cm) in similar cataclysmic variables, and estimate M^dot in each system through the relation L=(GM/R)*M^dot, where M is the mass of the star. From the available data we infer that p~0.9+-0.5. This radial dependence is consistent with radiatively inefficient accretion flows that either are convective or lose mass via a wind.

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Abraham Loeb, Ramesh Narayan, John Raymond. 2000-10-18. Does the Mass Accretion Rate Depend On the Radius of the Accreting Star?. https://doi.org/10.1086/318913

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