Volume 551, March 2013
|Number of page(s)||3|
|Published online||22 February 2013|
Coronal ejection and heating in variable X-ray sources
Nicolaus Copernicus Astronomical Center, ul. Bartycka 18,
Accepted: 16 December 2012
A sudden increase in stellar luminosity may lead to the ejection of a large part of any optically thin gas orbiting the star. Test particles in circular orbits will become unbound and will escape to infinity (if radiation drag is neglected) when the luminosity changes from zero to at least one half the Eddington value, or more generally, from L to (LEdd + L)/2 or more. Conversely, a decrease in luminosity will lead to the tightening of orbits of optically thin fluid. Even a modest fluctuation of luminosity of accreting neutron stars or black holes is expected to lead to substantial coronal heating. Luminosity fluctuations may thus account for the high temperatures of the X-ray corona in accreting black hole and neutron star systems.
Key words: accretion, accretion disks / scattering / X-rays: binaries / stars: winds, outflows / stars: neutron
© ESO, 2013
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