[vsnet-campaign-nova 950] Re: V2540 Oph - detection of period/s

[Alon Retter <retter@Physics.usyd.edu.au>]

Hello Taichi,

> > A nice paper by someone (no names) in
> > 1983 explained very nicely why novae can't be magnetic.
> 
>    Could you explain the point you thought that the paper is "nice"?
> (As everyone knows, not all papers are nice...)

The point was that the paper was full of physics and explained nicely
the problem. I must say, however, that I didn't go into details. When I
read the paper it was already known that there are magnetic novae.

> > This was inconsistent with the common belief of theoreticians
> > that it takes only a few decades for the disc to reform.
> 
>    This is not a common belief.  There still exists an argument among
> theoreticians.

This was the common belief. After the detection of superhumps in V1974 Cyg
about 2 years after outburst most theoreticians have changed their minds,
although there is one (no names!) who still thinks that there was no disc
in that nova about 3 yrs after discovery.
 
>    No one has ever denied the possibility of a nova from an AM CVn-type
> object.  You may have mistaken the argument against your talk; that was
> against your unification scheme between classical novae and X-ray novae
> (I remember someone asked what are X-ray novae you were referring to).

Sorry, but you are wrong about it. Most theoreticians hate this idea.
There were two main arguments against this idea:
1. there is not enough energy in helium burning on the shell for a nova.
2. it will become a supernova (the burning will reach the core).

I wrote a paper with this prediction a few years ago, but left it in the
drawer because of the strong hostality of most theoreticians. Apparently
they were wrong! I'm now planning to update the paper and submit it as
soon as possible. If only I had more time...

> > 4 years after outburst it is very bright in the X-rays despite of
> > its large distance, which is consistent with this suggestion.
 
>    Could you more explain the nature of the X-ray emission?  Couldn't it
> be a supersoft X-ray source as in GQ Mus and V1974 Cyg?  Is it pulsed?

Yes, it could be a supersoft X-ray source, but as novae usually turn off
in the X-ray after 1-2 years the simplest explanation is that this is an 
intermediate polar. Especially since the photometry suggests the presence
of several periodicities.

>    It is more likely that the lack of detailed physical mechanism in your
> model is not appealing to theoreticians to disprove your model.  In this
> case, the model is neglected rather than it survived.  On the other hand,
> Shaviv's model is rich in physics, and will be discussed (even may be
> refuted) in a reasonable way.  Such a model is a good model.

The paper in 1983 mentioned above was very rich in physics and according
to your criteria would be considered as a good model.
 
>    Will you reconsider your model if theories show that you are wrong?

I don't mind modifying my model. My point is mainly that there seems to be
a connection between novae that show the transition phase and intermediate
polars. I hope that you agree with this fact. I've actually discussed my
idea with a few theoreticians who inspired me to change the initial model.

I hope that the argument is over now. I've understood your point, and I
hope that you have understood mine.

Regards,
Alon Retter

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