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Escape, capture, and levitation of matter in Eddington outbursts

Författare och institution:
Adam Stahl (Institutionen för fysik (GU)); Wlodek Klu\'zniak (-); Maciej Wielgus (-); Marek A Abramowicz (Institutionen för fysik (GU))
Publicerad i:
Astronomy and Astrophysics, 555 s. artikel nr A114
Artikel, refereegranskad vetenskaplig
Sammanfattning (abstract):
Context: An impulsive increase in luminosity by one half or more of the Eddington value will lead to ejection of all optically thin plasma from Keplerian orbits around the radiating star, if gravity is Newtonian and the Poynting-Robertson drag is neglected. Radiation drag may bring some particles down to the stellar surface. On the other hand, general relativistic calculations show that gravity may be balanced by a sufficiently intense radiation field at a certain distance from the star. Aims: We investigate the motion of test particles around highly luminous stars to determine conditions under which plasma may be ejected from the system. Results: In Einstein's gravity, if the outburst is close to the Eddington luminosity, all test particles orbiting outside an "escape sphere" will be ejected from the system, while all others will be captured from their orbits onto the surface of another sphere, which is well above the stellar surface, and may even be outside the escape sphere, depending on the value of luminosity. Radiation drag will bring all the captured particles to rest on this "Eddington capture sphere," where they will remain suspended in an equilibrium state as long as the local flux of radiation does not change and remains at the effective Eddington value.
Ämne (baseras på Högskoleverkets indelning av forskningsämnen):
Fysik ->
Astronomi, astrofysik och kosmologi ->
stars: neutron / stars: winds, outflows / X-rays: binaries / scattering / accretion, accretion disks
Chalmers fundament:
Grundläggande vetenskaper
Postens nummer:
Posten skapad:
2013-08-12 10:15
Posten ändrad:
2016-04-28 09:57

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