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I did an investigation into MV Lyr which was published in the Czech publication Perseus a couple years ago. I found many periods, most if not all fleeting. I have an english language draft of the paper at http://vsnet.geocities.com/lcoo/mvly1999.htm It will be interesting to see if this 13 minute period persists. Regards, Lew --- "Ivan L.Andronov" <il-a@mail.ru> wrote: > 13.1-minute variations of MV Lyr > > MV Lyr has been observed in the Crimean Astrophysical > Observatory > by K.A.Antoniuk and N.M.Shakhovskoy during 12 nights > using the > 5-channel photometer-polarimeter constructed by > V.Piirola. > > Recently the star has shown a return to its active state > (for historical light curve, see > Andronov I.L., Fuhrmann B., Wenzel W. MV Lyrae : Entering > the > Period Gap ?-Astronomische Nachrichten, 1988, vol.309, > N.1, P.39-42. > and refs therein) > On JD 2452619-625, the mean brightness was <V>=13.79 with > a r.m.s. deviation from the mean of sigma=0.19, then the > star became brighter > <V>=12.64 (sigma=0.15) (JD 2452675-731). The most recent > night > JD 2452740 had shown an additional increase of the mean > brightness to > <V>=12.35 (sigma=0.07). > > At his high state, the variations at 13 minute time scale > have appeared. > The periodogram analysis of the deviations of the > observations from the > running parabola fit (Andronov I.L. Method of running > parabolae: spectral > and statistical properties of the smoothing function.- > Astron. Astrophys.Suppl., > 1997, Vol. 125, No 1, 207-217.) with a filter half-width > Delta t=15days > has shown a lot of peaks corresponding to the orbital > scale variability, > as well as to the short-term oscillations. > The highest peak corresponds to an ephemeris: > > TMax(U) = HJD 2452734.63125 + .00904586 * E (JD > 2452723-740) > +- .00007 +-.00000010 > TMax(R) = HJD 2452737.05132 + .00912842 * E (JD > 2452731-740) > +-.00008 +-.00000017 > The effective semi-amplitude of the variations decreases > with wavelength > (0.038+-.002 in U and 0.022+-.001 in R), but there seem > to be a modulation > of the amplitude with time. > > The one per cent discrepancy between the periods in the > ephemeris corresponds > to a daily bias (i.e. 110.548 and 109.548 cycles per day, > respectively), > thus new observations are needed to make a proper cycle > numbering and to > check possible coherency of such oscillations. > > Such a period has not been detected during previous > active states > in 1989 > (Andronov I.L., Borodina I.G., Chinarova L.L., Fuhrmann > B., Kolesnikov > S.V., Korth S., Pavlenko E.P., Pikhun A.I., Shakhovskoj > N.M., Shugarov > S.Yu., Wenzel W. MV Lyrae: the cataclysmic variable, > which > returned to its normal activity state.- Commun.Spec. > Astron.Obs., 1992, > v.69, p.125-136.) > in 1992-1993 (Kraicheva Z., Stanishev V., Genkov V. > MV Lyrae: Photometric study at high state, > Astron. Astrophys. Suppl. Ser. 134, 263--270 (1999)) > or in 1996 (Pavlenko E.P., Shugarov S.Yu. Photometric > study > of the nova-like variable MV Lyrae during an enormous > outburst > in 1997, Astron. Astrophys. 343, 909--915 (1999)) > > I.L.Andronov il-a@mail.ru , http://il-a.pochtamt.ru > K.A.Antoniuk antoniuk@crao.crimea.ua > N.M.Shakhovskoy shakh@crao.crimea.ua > > ===== 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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