The accretion geometry of intermediate polars
نویسنده
چکیده
Intermediate polars range from systems which accrete entirely via discs (e.g. EX Hya) through systems which combine disc and disc-overrow accretion (e.g. FO Aqr) to discless accretors (e.g. RX 1712{ 24). The accretion curtain model provides a good description of the optical spin-pulses, while in the X-ray regime, occultation combines with absorption to create complex pulse-prooles.
منابع مشابه
Recent results on intermediate polars
I review recent activity in the field of intermediate polars, concentrating on: the mode of accretion (disc-fed, disc-overflow or discless); accretion curtains (the transition region and the accretion footprint); X-ray pulse profiles (occultation and absorption effects); accretion columns (mass determinations, line-broadening, the soft X-ray component), and outbursts in intermediate polars.
متن کاملDisc-overflow Accretion in Intermediate Polars
We have recently realised that intermediate polars accrete in a range of modes. While accretion is predominantly through an accretion disc, in some systems the accretion stream overrows the disc and interacts with the magnetic eld directly. In RX 1712{24, discless accretion dominates. I review the current status of these observations, concentrating on the information from the X-ray lightcurves.
متن کاملThe Intermediate Polars
Recently discovered intermediate polars extend the limits of known behaviour. They now ll the range between, and overlap with, non-magnetic CVs and AM Hers. They have a wide range of asynchronism, a full range of eld strengths, and several diierent accretion modes and pulsation mechanisms. I highlight (i) a puzzle over the symmetry between magnetic poles, (ii) the X-ray spectra, (iii) the simil...
متن کاملThe effects of tidally induced disc structure on white dwarf accretion in intermediate polars
We investigate the effects of tidally induced asymmetric disc structure on accretion onto the white dwarf in intermediate polars. Using numerical simulation, we show that it is possible for tidally induced spiral waves to propagate sufficiently far into the disc of an intermediate polar that accretion onto the central white dwarf could be modulated as a result. We suggest that accretion from th...
متن کاملStream-fed Accretion in Intermediate Polars
I review the observational evidence for stream-fed accretion in intermediate polars. Recent work on the discless system V2400 Oph confirms the pole-flipping model of stream-fed accretion, but this applies only to a minority of the flow. The bulk of the flow is in the form of blobs circling the white dwarf, a state which might have been a precursor to disc formation in other IPs. I also discuss ...
متن کامل