Results on EUVE J1429-38.0

a.k.a. Cen 2, V895 Cen

This CV was observed at Woomera from February 1996 to September 1998. Jonathan Kemp of the CBA (now working at JACH on Hawaii) very kindly obtained some data at CTIO during February, March and August 1998.

It was found to be variable both in brightness and shape of the light-curve. Its orbital period has been found to be 17155.57+-0.02s from the Woomera data over the above-mention time span. A phase zero of HJD 2450289.027 was used for the following figures.

At phase zero (i.e. mid-eclipse), all accretion sources are eclipsed. Initially, it was thought that a partial accretion disc formed around the primary during active states, and that the variable size and brightness of this component were responsible for many features of the light-curves. However, recent published results from high-speed photometry and modelling suggest that an accretion stream (and its interaction with the primary) alone is sufficient to explain the observed light-curve.

Changes may be observed from day-to-day, and it is possible that high-low or low-high state transitions occur within a time-scale of two months. However, the Woomera data are not dense enough in order to determine this latter point more accurately.

Differential magnitude vs. HJD : swapping between active and inactive states is clear. Note that this plot includes only those nights for which the full eclipse portion of the light-curve were observed.

Diff. mag. vs. phase : the range in waveforms is clear; inactive is sinusoidal from ellipsoidal modulation of the secondary star; active, shows ellipsoidal modulation but with a deep eclipse at phase zero. There are also many intermediate states.

CTIO V-band magnitude vs. phase : (from March 2nd, 1998) the ellipsoidal modulation, some flaring, and features within the eclipse are visible. The latter include stream ingress/egress, disc (and primary star) ingress/egress, and total eclipse.