[vsnet-alert 2644] Nova Mus 1998 is an IP?

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

Hello vsneters and nova funs,

Further photometry by Bill Liller and Gordon Garradd on Nova Mus 1998
confirmed the presence of period/s (although not the previously suggested
one). There is certainly a period of ~4.91 c/d~ 4.9 hr (probably the
orbital period). It is seen in 2 different parts of the data. The power
spectrum is very rich with more periods - ~1.9 hr (a spin period-?);
it's 1st harmonic; a beat period (Wspin-Worb), and probably even
Wspin+Worb. The periods are still subjected to the alias problem.
Altogether it looks like an intermediate polar.

Implications are important. It means that the common envelope phase 
has been ended, and we can see into the binary system. It rules
out the suggestion that the oscillations during the transition phase 
are due to oscillations in the common envelope. Secondly, it suggests
that the transition phase might occur only in intermediate polar
systems (more examples I know - DQ Her, GK Per). Can anyone comment
on this suggestion?

More data is still needed in order to confirm the intermediate polar 
model of Nova Mus. The observations by Liller and Garradd are considered
'bad' in the sense that the filters that they used (Liller - BVR,
Garradd - clear) comprise the H-alpha nebular line). So perhaps
even observations through an H-alpha filter could be useful.

Latest report on the nova brightness - Mv=13.4 (R. Stubbings - 16/2/99).

Let me mention, that without the variable stars net, this important
result would have surely missed. 

Alon
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   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)
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