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Astron. Astrophys. 351, 185-191 (1999)

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Estimation and effects of the mass outflow from shock compressed flow around compact objects

Sandip K. Chakrabarti

S.N. Bose National Centre for Basic Sciences, JD-Block, Sector III, Salt Lake, Calcutta 700091, India (chakraba@boson.bose.res.in)

Received 10 May 1999 / Accepted 13 August 1999


Outflows are common in many astrophysical systems which contain black holes and neutron stars. Difference between stellar outflows and outflows from these systems is that the outflows in these systems have to form out of the inflowing material only. The inflowing material can form a hot and dense cloud surrounding the compact object, either because of a centrifugal barrier, or a denser barrier due to pair plasma or pre-heating effects. This barrier behaves like a stellar surface as far as the mass loss is concerned. We estimate the outflow rate from the regions of shock compressed flow. The outflow rate is directly related to the compression ratio of the gas at the shocks. These estimated rates roughly match the rates in real observations as well as those obtained from numerical experiments. In special geometries, where the solid angle of the outflow is higher, the disk evacuation takes place creating quiescence states. Outflows are shown to be important in deciding the spectral states and Quasi Periodic Oscillations (QPO) of observed X-rays coming out of compact objects.

Key words: accretion, accretion disks – black hole physics – shock waves – stars: neutron – stars: individual: SS433 – stars: winds, outflows

© European Southern Observatory (ESO) 1999

Online publication: November 2, 1999