What I learned from C. Knigge's Paper

(Knigge 2012) shows a good summary of Cataclysmic Variables in Globular Clusters. Here are a few points I thought were interesting.

Location, Location, Location or CVs in a crowded environment

It matters in real estate and it also seems to play a factor in the formation and evolution of compact objects such as the Cataclysmic Variables.

Time is Gold or the Period Gap in the CVs

Period is an important factor that can help us constraint some models of WDs binary systems. The minimum period of 80 min is set roughly by the size size of the companion star. We have a good and the most significant features is what is refer to as the “period gap”. For CVs evolution see paper (). But this is not for the CVs in the Globular Clusters. This is not True for the few (only 15) samples of the CVs for which we know the period. We only know for two in NGC 6397 (reference for that). U23 and U17.

With cross correlation the idea would be to get the period. I can check with U23 that we have the period and the hope is to get the period for U17. The period of U10 is also know.

He II

Is due to EUV but also seen in

The sleeping beauties

WZ Sge vs. DQ (Magnetism vs Explotion)

We want to see explotion. DNe have been confirmed for two CVs. Magnetic dont tend to explote since this is duw to accumulation in the accretion disk, but there are exception. Two have seen exploted (U19 and U17). See Shara and Knigge paper. So maybe they are not DQ systems of also called intermediate polars.

Also they could be WZ Seg that wait a long time to explote. Cohn suggest the faint ones are this. (Are this the sleeping beauties)? I dont think so, but they show emmission within absroption as show in this spectra (ref to WZ).

The He II line is also not complusive evidence for IP since some DNe also have this lines.

DNe and Nova and sleeping beauties