[vsnet-chat 469] Re: Nova RW UMi 1956 and V603 Aql -answer to Taichi Kato

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

Dear Dr. Retter,

> The correct ref. is Kukarkin 1962, IBVS no. 18. (30/12/62 became 1963!)
> However, the claim for the pre-nova with mv=21-21.5 comes from Howell,
> 1988, IAUC, 4672. I guess that since the estimations of about mv=19
> before (1987) and after (1989) of this measurement make it very
> suspicious, and you are probably right about it.

    I think the original claim of the possible faint state of this post-
outburst nova should be checked (any images available?) before reaching
any definite conclusion.  As you have shown, I would not wonder if the star
(assuming the below-the-gap nature) wanders between 'high' (permanent
superhumper) and 'low' (SU UMa) states.  If so proven, this object may
become the first such.

> In addition, this nova is on our program, too. First results suggest
> that the orbital period is much longer than 2 hr. My guess is that it
> is an intermediate polar.

    I am pleased to know this object is so intensively monitored.  It would
be very interesting to know its true orbital period, since the object
is suspected to belong to the old population (from its high-Z), and the
orbital period might provide a test for the evolutionary model of halo CVs.
Any indication of a coherent signal?

> >    Being abobe the period gap, I would not wonder if V603 Aql had the same
> > magnitude before and after the outburst.
> > 
> 
> I don't see any special reason why novae above the period gap should
> return to their pre-outburst state, while shorter period novae will
> be stuck above their quiescent state. Do you?

    My notion was not that above-the-gap novae should return to their
pre-outburst states, but that above-the-gap novae might have been normal
novalike (NL) variables before nova eruption.  So I don't wonder if these
novae had high mass-transfer rates before eruption as they do today.
This is probably not the case for below-the-gap novae.  If they had high
mass-transfer rates before eruption, we need a (new) mechanism of
maintaining such high mass-transfer rates, since they unlikely have
nova-heated secondary stars before eruption, which are sometimes thought
to be the cause of enhanced mass-transfer.

    By the way, are there any established cases of above-the-gap novae
(aside from the peculiar magnetic nova, V1500 Cyg) which show much brighter
quiescence after the nova explosion?  It is interesting even the fastest
nova (V838 Her) has returned to its pre-outburst magnitude.

Regards,
Taichi Kato

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