Stream-fed Accretion in Intermediate Polars：（小溪的水流量吸积在中间高偏振星）.pdfVIP

The Physics of Cataclysmic Variables and Related Objects ASP Conference Series, Vol. XXX, 2002 B.T. G¨ansicke, K. Beuermann, K. Reinsch Stream-fed Accretion in Intermediate Polars Coel Hellier Astrophysics Group, Keele University, Staffs ST5 5BG, U.K. 2 0 Abstract. I review the observational evidence for stream-fed accretion 0 in intermediate polars. Recent work on the discless system V2400 Oph 2 confirms the pole-flipping model of stream-fed accretion, but this applies n only to a minority of the flow. The bulk of the flow is in the form of a J blobs circling the white dwarf, a state which might have been a precur- sor to disc formation in other IPs. I also discuss work on the systems 9 2 with anomalously long spin periods, V1025 Cen and EX Hya. There are arguments both for and against stream-fed accretion in V1025 Cen, and 1 further work is necessary before reaching a conclusion about this system. v 5 7 4 1 1. Introduction 0 2 0 Early work on intermediate polars (IPs), taking a lead from studies of DQ Her, / tended to assume the presence of an accretion disc. The accretion stream would h p feed the outer disc, as in non-magnetic systems, and the magnetic field would - disrupt the inner disc and so channel the accretion along field lines onto mag- o netic polecaps. Hameury, King, Lasota (1986) and Lasota King (1991) r t presented theoretical arguments