The new AM CVn star in Hydra

High speed photometry of the new AM CVn star in Hya (previously known as SN2003aw), spectroscopically identified by Chornock & Filippenko, shows it to have a superhump period of 2041.5 +/- 0.3 s. We find a range of brightness from V ~ 16.5 to 20.3, presumably caused by variations in the rate of mass transfer. In the intermediate state the system cycles in brightness with a period of ~ 16 h and range >= 0.4 mag. There are sidebands to the principal frequencies in the Fourier transform which have constant frequency difference from the superhump harmonics.Comment: 5 pages, 6 figures. Accepted for publication in MNRA

Spectroscopy and near-infrared photometry of the helium nova V445 Puppis

Nova Puppis 2000 (V445 Pup) has been proposed as the first example of a helium nova. Recent optical spectroscopy of V445 Pup at V=19.91 mag obtained with IMACS on the 6.5-m Magellan telescope, shows that the spectrum consists of HeI, [OI], [OII] and [OIII] emission lines and no hydrogen is present. The spectroscopy shows an expanding nova shell with blue- and redshifted velocity components around +/- 850 km/s and +/- 1600 km/s. Images taken with Magellan under very good seeing conditions (FWHM ~ 0.6") shows V445 Pup to be extended (full width at zero intensity ~ 1.9") and elongated (position angle ~ 150deg). We have followed the secular evolution of V445 Pup since the decline from (optical) maximum, at near-infrared wavelengths (J, H and Ks) using the Infrared Survey Facility (IRSF) at the Sutherland site of the South African Astronomical Observatory. We find that V445 Pup is still covered by a dense dust shell more than three years after its outburst.Comment: 2 pages, 1 figure. To appear in `The Astrophysics of Cataclysmic Variables and Related Objects', eds. J.M. Hameury and J.P. Lasota (ASP Conf. Ser.

Rapid Oscillations in Cataclysmic Variables, and a Comparison with X-Ray Binaries

We compare some of the properties of rapid oscillations in cataclysmic variables and X-Ray binaries. In addition to the earlier recognition that both types possess the same correlation between high and low frequency quasi-periodic oscillations, we have now found that the dwarf nova VW Hyi in its late stages of outburst shows the 1:2:3 oscillations harmonics that are seen in some neutron star and black hole X-Ray binaries. We point out that the behaviour of the dwarf nova WZ Sge has some similarities to those of accreting millisecond pulsars.Comment: 10 pages, 4 figures (needs AIP style file). To appear in the conference proceedings of `Interacting Binaries: Accretion, Evolution & Outcomes' (Cefalu, July 4-10 2004

High speed photometry of faint cataclysmic variables - VI. Car2, V1040 Cen, Ha 075648, IL Nor (Nova Nor 1893), HS Pup (Nova Pup 1963), SDSS J2048-06, CSS 081419-005022 and CSS 112634-100210

We have observed 8 faint cataclysmic variable stars photometrically. The nova-like Car2 was extensively sampled but showed little variability. V1040 Cen was observed near the end of a dwarf nova outburst and possessed dwarf nova and quasi-periodic oscillations. Ha 075648 has strong large amplitude flickering and a possible orbital modulation at 3.49 h. The correct identification for the nova remnant IL Nor (Nova Nor 1893) has been established. HS Pup (Nova Pup 1963) has a possible orbital period of 3.244 h. SDSS J2048-06 is a low mass transfer dwarf nova that in quiescence shows slow variations at 7.67 h (though poorly sampled with our observations) and an orbital modulation at 87.26 min. The dwarf nova CSS 081419-005022 has an orbital period of 1.796 h and the eclipsing dwarf nova CSS 112634-100210 has an orbital period of 1.8581 h.Comment: 7 pages, 15 figures. Accepted for publication in MNRA