ROTSE3 CV: ROTSE3 J015543.40+002807.2

This is a quick report on ROTSE observations of the SDSS cataclysmic variable SDSSp J015543.40+002807.2, described in Szkody et al. (SDSS pub 91) as an 'AM Her system with a magnetic white dwarf or a high accretion rate SW Sex star'. It is discussed quite a bit in this paper because it has rather bizarre properties.

In ROTSE3 this object shows up as strongly variable, running between 15.5 and 18 in R. Most remarkably, it seems to show very short period variability. ROTSE3 takes images in pairs; two 60 second exposures back to back. In two of these exposures, this object varies from 17.6 to 16.3. There is a gap of only 9 seconds between the images. I have examined the images and the variation certainly looks real. If you look closely at the other pairs, you can see several which also show significant discrepancies. It is possible these discrepancies are also real, and that this object shows strong flickering behavior.

There are several plots contained in this postscript file that illustrate the object. First is the lightcurve. The diamonds are SDSSp_0155, the crosses a random comparison star. The strong variability event is around day 10. Here are the crucial measurements:

Time (MJD)Magnitude (mROTSE)Elapsed time (s)

The remaining three figures are the actual images in the first three of these epochs. You can see that it really does seem to vary by a factor of 1.3 in this one minute period.

  • Postscript file with various plots