[vsnet-chat 468] Nova RW UMi 1956 and V603 Aql -answer to Taichi Kato

[Alon Retter <alon@wise.tau.ac.il>]

>    According to the table caption of this Howell et al.'s paper, the
> reference of the post-eruption magnitude should be Kularkin's IBVS 18.
> However, there does not seem to be such; the POSS exposure was taken
> only before the nova eruption.  There are several other good post-outburst
> quiescence photometry of RW UMi: Cohen (ApJ 292, 90), and Kaluzny and
> Chlebowski (Acta Astron. 39, 35), both of which give magnitudes of
> 18.5-19.  If RW UMi is indeed a below-the-period-gap object, what about
> this in your calculation?  Using the observed amplitude (present-maximum)
> of 12~13 mag and the absolute maximum magnitude of slow novae, the present
> magnitude might seem to become critically close to the lower limit of an
> thermally stable accretion disk.
> 

Dear Dr. Kato,

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. It seems that the nova
hasn't returned yet to its pre-outburst luminosity.

Anyway I tested today this nova, too. My calculations for the nova
don't give any conclusion.  The critical visual magnitude for passing
the thermally stable line is about 17.6-19.9 (the main uncertainty
comes from the distance), when the present mag. of the nova is around
mv=19.

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.  More observations are needed especially
since the star is very faint.  Collaboration is very important in order
to eliminate the aliases - we have lots of them. Anyone wishes to join 
us? 

>    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?


Greetints
Alon Retter

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