[vsnet-campaign-nova 947] Re: V2540 Oph - detection of period/s

[Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>]

Re: V2540 Oph - detection of period/s

Dear Alon,

> I've heard Nir Shaviv's talk in the nova conference in Sitges and have
> already printed his summary mentioned below for further reading.
> 
> While Nir has a simple theoretical explanation to the transition phase,
> it does not mean that it is the correct one!

   As you may have noticed, Nir Shaviv has recently produced a number of
works in addition to the Sitges proceeding (cf. ApJ 549, 1093 (2001) and
MNRAS 326, 126 (2001), both of which are very insightful).  The most
important advantages of Shaviv's theory over yours are that the theory
has solved a number of previously known inconsistensies (i.e. mass loss
etc.) between observation and theory (not only an explanation of
transition phase), and that it also showed that novae should pass a
region with no steady state (transition phase) -- they are a good
indication that the theory is approaching the correct way.

   This theory seems to be a natural extension of the wind theory by Kato
and Hachisu (which you well know), and Shaviv has apparently made a further
progress since then in modeling the oscillation (e.g. identification of the
restoration force etc., which was not apparent in the 2001 MNRAS paper),
as can be seen in the figure of the Sitges proceeding.

> As for the physics behind my model, I suggested that the reformation of
> the accretion disc after the nova outburst in intermediate polars and the
> interaction of the inner part of the disc with the magnetosphere of the
> white dwarf is the reason for the oscillations.

   How magnetosphere interacts with the disk to produce oscillations?
What is the necessary magnetic field?  What would be the oscillation period?
Why such oscillations are not observed except during the transition phase?
A real "predictive power" would be able to, at least in some part, give
an answer.  Without a physical basis, we can't tell the differecence between
the claimed predictive power and fortune-telling.

   What is apparently needed is not more observation, but your
reconsideration.

Regards,
Taichi Kato

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