Hellier, C (2014) The Magnetospheric Boundary in Cataclysmic Variables. EPJ Web of Conferences: The Space Photometry Revolution – CoRoT Symposium 3, Kepler KASC-7 Joint Meeting, 64. ISSN 2100-014X

[thumbnail of 1312.4779v1.pdf]
1312.4779v1.pdf - Published Version
Available under License Creative Commons Attribution.

Download (351kB) | Preview


The magnetic cataclysmic variables (MCVs) present a wealth of observational diagnostics for studying accretion flows interacting with a magnetosphere. Spin-period pulsations from the rotation of the white dwarf are seen in optical light, in the UV and X-ray bands, and in polarimetry, and modelling these can constrain the size and location of the accretion footprints on the white-dwarf surface. Tracing these back along field lines can tell us about the transition region between the stream or disk and the magnetosphere. Further, optical emission lines give us velocity information, while analysis of eclipses gives spatial information. I discuss MCVs (particularly FO Aqr, V405 Aur, XY Ari and EX Hya, but also mentioning PQ Gem, GK Per, V2400 Oph, HT Cam, TX Col, AO Psc, AE Aqr, WZ Sge, V1223 Sgr and DQ Her), reviewing what observations tell us about the disk-magnetosphere boundary. The spin-period variations are caused by a mixture of geometric effects and absorption by the accretion flow, and appear to show that the accretion disk feeds onto field lines differently in different systems, being sometimes along field lines ahead of the magnetic pole and sometimes behind the pole. During outbursts, when the accretion flow increases by orders of magnitude, the disk pushes the magnetosphere inwards, and appears to feed field lines over a much greater range of magnetic azimuth. The non-equilibrium outburst behaviour shows an even richer phenomenology than in quiescence, adding DNOs and QPOs into the mix.

Item Type: Article
Additional Information: This work is made available online in accordance with publisher policies
Subjects: Q Science > QB Astronomy
Divisions: Faculty of Natural Sciences > School of Physical and Geographical Sciences
Related URLs:
Depositing User: Symplectic
Date Deposited: 03 Nov 2016 11:28
Last Modified: 03 Nov 2016 11:28
URI: https://eprints.keele.ac.uk/id/eprint/2419

Actions (login required)

View Item
View Item