X-Ray Photoionized Bubble in the Wind of Vela X-1 Pulsar Supergiant Companion

0388466 - ASÚ 2013 RIV US eng J - Článek v odborném periodiku
Krtička, J. - Kubát, Jiří - Skalický, J.
X-Ray Photoionized Bubble in the Wind of Vela X-1 Pulsar Supergiant Companion.
Astrophysical Journal. Roč. 757, č. 2 (2012), 162/1-162/6. ISSN 0004-637X. E-ISSN 1538-4357
Grant CEP: GA ČR GA205/08/0003
Institucionální podpora: RVO:67985815
Klíčová slova: hydrodynamics * radiative transfer * early-type stars
Kód oboru RIV: BN - Astronomie a nebeská mechanika, astrofyzika
Impakt faktor: 6.733, rok: 2012

Vela X-1 is the archetype of high-mass X-ray binaries (HMXBs), composed of a neutron star and a massive B supergiant. The supergiant is a source of a strong radiatively driven stellar wind. The neutron star sweeps up this wind and creates a huge amount of X-rays as a result of energy release during the process of wind accretion. Here, we provide detailed NLTE models of the Vela X-1 envelope. We study how the X-rays photoionize the wind and destroy the ions responsible for the wind acceleration. The resulting decrease of the radiative force explains the observed reduction of the wind terminal velocity in a direction to the neutron star. The X-rays create a distinct photoionized region around the neutron star filled with a stagnating flow. The existence of such photoionized bubbles is a general property of HMXBs. We unveil a new principle governing these complex objects, according to which there is an upper limit to the X-ray luminosity the compact star can have without suspending the wind due to inefficient line driving.
Trvalý link: http://hdl.handle.net/11104/0217370