We study backreaction of accreting matter onto a spherically symmetric black
hole in a perturbative way, when accretion is in a quasi-steady state. General
expressions for corrections to the metric coefficients are found in the
Eddington-Finkelstein coordinates. It is shown that near the horizon of a black
hole, independently of the form of the energy-momentum tensor, the leading
corrections to the metric are of the Vaidya form. The relation to other
solutions is discussed and particular examples are presented.Comment: 12 pages, v.2: references added, typos corrected, matches published
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