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Lew Cook provides the following information. We are also interested in the nature of flickering and quasi-periods, so the lack of strict coherence is not a major problem in this research. It looks like that the currently dominant periods of the short-period variations are shorter than what Lew observed in 1999. Regards, Taichi Kato VSNET Collaboration team === Date: Sun, 1 Jun 2003 22:42:51 -0700 (PDT) From: Lew Cook <lcoo@yahoo.com> Subject: Re: [vsnet-campaign-nl 122] MV Lyr: strong short-period oscillations Dear Taichi: I looked at MV Lyr in 1999 when it was bright. I wrote up an analysis for the Czech publication Perseus. Then I found similar type of variations, but I found little correlation in the strong periodicities from one night to another. There were some periodic signals, but the star has a lot of strong flickering and this naturally compounds the periodicity analysis. An excerpt: "A 0.10 magnitude variation at a period of 0.157875 days was found. A phase diagram of it is presented in Figure 6a. At a 19 per cent excess of the orbital period, this seems too long a period for a superhump period and may be a chance occurrence in the irregular variation of the star. Judging from the shape of the curve, it could be a superposition of several flickers which happened to satisfy a period of some multiples of 227 minutes. There was no peak in the periodograms nor any discernable pattern in phase diagrams at or near the orbital period of 0.1329 days. Another signal at 0.13762 day, near the superhump period detected by Skillman et al (0.1378 day), is also present with an amplitude of 0.08 magnitude (Fig. 6b), and one at 0.13189 days at 0.08 magnitude. An alias of the 0.157875 day peak occurred at 0.13778 d. The other period noted by nearly every investigator, around 48 minutes, is also present at 0.04 magnitude variation at 47.9 minutes (0.0332615 days) shown in Fig. 6c. " THis is a difficult star. I have an English language draft of my Perseus article on my web site at http://vsnet.geocities.com/lcoo/mvly1999.htm ===== Regards, Lew CBA Concord http://vsnet.geocities.com/lcoo/eng29.htm The CBA Concord telescope is in the debugging process CBA Pahala http://vsnet.geocities.com/lcoo/pahala.htm
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