Accretion processes in cataclysmic variables: Insights from optical transient surveys
Presented by Ms. Mokhine MOTSOALEDI on 10 Jul 2014 from 15:00 to 15:20
Type: Oral Presentation
Track: Track D1 - Astrophysics
Cataclysmic variables (CVs) are mass transferring binary stars consisting of a low mass main sequence (MS) donor star and an accreting white dwarf star. AM CVn stars are a subclass of cataclysmic variables which have helium-rich donors (a white dwarf, a helium star or an evolved MS star). Their most defining features are their ultra-short orbital periods and helium-dominated spectra. The presence of a strong magnetic field would affect the trajectory of the mass flow, causing it to follow a stream along the magnetic field lines on to the magnetic poles of the white dwarf. An intermediate polar would truncate the accretion disc on the inside whereas a polar prevent an accretion disc from forming at all. The Catalina Real-time Survey (CRTS) is a synoptic transient survey which detects transients that vary in brightness over 2 mags over a large area of sky. In the past 15 years, wide area surveys such as the CRTS have greatly increased the number of known CVs (> 1000). The nine year observing baseline of the CRTS makes it suitable for identifying magnetic CVs from their low-to-high state transistions, or vice versa. I observed sources from the CRTS at the South African Astronomical Observatory in Sutherland. I've discovered 3 new AM CVns (~10% of the known AM CVns) and I'm currently exploring ways to identify and characertise magnetic CVs from the CRTS.
Dr David Buckley (SALT), A/Prof Patrick Woudt (UCT), Prof Brian Warner (UCT), Dr Stephen Potter (SAAO)