IPs
AE Aqr
Related Systems
Candidates
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When do I accept a system as an IP?On this site, I have the absolute power to decide which systems I include as IPs, which as candidates, and which to ignore. Some systems so obviously belong to the class, there are no arguments (e.g., AO Psc). But there are borderline systems, for one reason or another.I've decided to write this page because of HT Cam. Now that Joe has decreed this a genuine DQ Her system, I'm including it to my list of genuine IPs. It's not that I didn't trust Gaghik's results; on the contrary, I trusted his own judgement that it was a candidate IP. I think I agreed with his classification as a candidate IP, and because of the short outbursts, considered it a strong IP candidate. When the classification depends on the optical periodicity, it should be coherent and persistent to a high degree. It has to be repeatedly observed, ideally over several years; I'd like to see a long-term spin ephemeris to accept a CV as an IP solely based on an optical periodicity. Jonathan Kemp, Joe Patterson and their CBA colleagues have done just that for HT Cam, so I updated the status of this sytem even before the paper was official accepted. If you see apparent modulations for a few cycles --- don't get too excited. I think every CV observer should read Warner's Warning before attempting to identify periodicities in CVs. If I were writing my papers on KO Vel now, with the same data, I would probably write a very different paper. When X-ray pulses are involved, I would relax the requirement --- two independent X-ray pulse period determinations would be sufficient for me (assuming it is known to be a CV and the periods agree). It is not sufficient for a sub-orbital X-ray periodicity to be seen once. Such one-time-only X-ray periodicities have been seen in many non-magnetic CVs (see my list of Poor Candidates). Usually in such systems, different periods are seen in different X-ray observations, proving that these X-ray modulations are not tied directly to the spin period of the white dwarf.
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This file was last modified on Tuesday, 28-May-2002 13:20:29 EDT |