[vsnet-alert 3469] Re: Nova Sgr 1998 brightening!

[Alon Retter <ar@astro.keele.ac.uk>]

Dear readers,

This is very interesting!

Nova Sgr 1998 is most probably a permanent superhump system
(Lipkin, personal communication). Thus, it cannot have dwarf 
nova outbursts. Short-term outbursts have been observed in a 
few systems (TV Col, AM CVn, and even once in Nova V705 Cas 
1993). To explain this behaviour, I prefer the idea of Hellier 
and Buckley (1993), who suggested that these mini-outbursts
are mass transfer events. However, other explanations are 
possible (e.g. magnetic activities as in our sun...). I, 
therefore, suspect that the nova will return back to its
'quiescence' state (the level before this event, not the nova 
event) very fast. If I am wrong, though, and this would be
a long dwarf nova like outburst, it should pose serious
difficulties to the Disc-Instability model.

Observers are encouraged to confirm this result, and to check 
the current magnitude of the nova.

Regards,
Alon
-------------------------------------------------------------------------
   Dr. Alon Retter         Tel. (work)     +44-(0)1782-58-3493  
   Physics Dept.           Fax  (work)     +44-(0)1782-711093 
   Keele University        -----------------------------------
   Staffordshire           'As a scientist I don't believe myself, so
   ST5 5BG, U.K.            why should I believe you?' (A.R. 1965-2085)
-------------------------------------------------------------------------
On Mon, 13 Sep 1999, Taichi Kato wrote:

> Nova Sgr 1998 brightening!
> 
>   T. Watanabe reports a considerable brightening of Nova Sgr 1998.
> 
>   YYMMDD(UT)   mag  observer
>   990818.517  14.04Rc  (S. Kiyota)
>   990818.521  13.53V  (S. Kiyota)
>   990818.528  14.16B  (S. Kiyota)
>   990828.719   132  (B. Monard)
>   990831.531   139  (T. Watanabe)
>   990905.497  14.18Rc  (S. Kiyota)
>   990905.500  15.32V  (S. Kiyota)
>   990912.507   130  (T. Watanabe)
> 
>

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