[vsnet-chat 1600] Re: [vsnet-alert 2575] Nova Mus 98 - a possible periodicity

[Taichi Kato <tkato>]

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

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