Re: [vsnet-alert 2575] Nova Mus 98 - a possible periodicity Dear Dr. Retter, > Yes, this is certainly a possibility. The large outburst amplitude and the > presence of the possible period might be explained by a magnetic nova > model, as well. Yes, it's another fascinating possibility. As may be remembered, at least one magnetic nova (V1500 Cyg) indeed exists, and showed large-amplitude variation which has been interpreted as the "search-light" phenomenon. It would be interesting to search for this possibility in Nova Mus 1998, too. As a matter of fact, my time-series pghotometry on Nova Her 1991 (V838 Her) was motivated by the hope of detecting similar modulations. > An intriguing suggestion is that the oscillations observed during > the transition phase are caused by the reformation of the accretion disc. > Anyway, this question is still opened. I tend to think these oscillation as some kind of pulsation (or instability) in the expanding shell (wind). I obtained some intermediate band photometry in Nova Cas 1993 (V705 Cas), which showed ~2-day oscillation, and found color changes and light curve profile similar to those of pulsating variable. But it would be still premature to conclude anything from this finding. I hope someone in the southern hemisphere follow the oscillation cycle by multicolor photometry, and possibly by spectroscopy to search for a signature of pulsation. Regards, Taichi Kato