[Message Prev][Message Next][Thread Prev][Thread Next][Message Index][Thread Index]
[vsnet-chat 2277] Re: (fwd) Re: Strong oscillation in Nova Cir 1999?
- Date: Thu, 2 Sep 1999 10:35:18 +0100 (BST)
- To: vsnet-chat@kusastro.kyoto-u.ac.jp
- From: Alon Retter <ar@astro.keele.ac.uk>
- Subject: [vsnet-chat 2277] Re: (fwd) Re: Strong oscillation in Nova Cir 1999?
- cc: tkato@kusastro.kyoto-u.ac.jp, Berto Monard <lagmonar@csir.co.za>
- In-Reply-To: <s7ce5c79.009@csir.co.za>
- Reply-To: Alon Retter <ar@astro.keele.ac.uk>
- Sender: owner-vsnet-chat@kusastro.kyoto-u.ac.jp
Dear Berto, Taichi and others,
If the oscillation in Nova Cir 1999 are real or not:
I just want to note that Nova V1668 Cyg 1978 had a similar behaviour.
A periodicity of ~13 hours was discovered in its early stages, and was
interpreted as oscillations in the common envelope surrounding the
binary system. It is very different from the orbital period of ~3 h
discovered later. To my knowledge, it has never been observed in any
other novae.
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 Thu, 2 Sep 1999, Berto Monard wrote:
> Dear Taichi and readers,
>
> I would like to comment on the posting from Brian Fraser.
>
> There is a definite possibility of magnitude estimate off-sets due to
> personal differences in red/blue sensitivity and perhaps here and
> there some personal bias regarding to what possibly is the expected
> magnitude of the nova at that moment.
> However I disagree that this should be generalised and that I
> therefore wish to state my agreement with Taichi's statement that the
> oscillations are a true representation of the nova's past behaviour. I
> have no doubt that the nova has been down to (at least) around
> magnitude 8.7 on 24/8 (as reported by experienced observers) and that
> it re-brightened afterwards and reported 12 hours later at around 8.0
> by experienced observers from other continents. This oscillation has
> repeated itself with a diminishing amplitude during the following 24 h
> as seen in the lightcurve by experienced observers.
> There is no doubt in my mind that a (probably aperiodic) oscillation
> in the luminosity of Nova Cir 1999 took place.
>
> Best regards,
>
> Berto Monard
> Pretoria
>
> >>> Taichi Kato <tkato@kusastro.kyoto-u.ac.jp> 09/02 10:40 AM >>>
> >From brian.fraser@Macsteel.co.za Thu Sep 2 15:25 JST 1999
> From: "brian.fraser" <brian.fraser@Macsteel.co.za>
> To: Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>
> Subject: RE: [vsnet-chat 2273] Strong oscillation in Nova Cir 1999?
> Date: Thu, 2 Sep 1999 08:14:47 +0200
> MIME-Version: 1.0
> Content-Type: text/plain
> Content-Length: 1428
>
> Hello Taichi,
> I was thinking about this topic when I came upon this possible
> explanation.
> It looks to me as though each observer has his "personal bias" ie when
> he is
> in doubt he goes for a lower estimate or maybe a higher estimate.
> So you are looking at the results from one or two observers in
> Australia,
> one or two in South America, some in South Africa. If an active
> observer in
> Australia is consistently over-estimating the magnitude (just by 0.1
> or 0.2)
> and an observer in South Africa is consistently under-estimating, it
> could
> quite easily look as though there was a one day cycle. Maybe this is
> what
> is happening??
> Just a thought,
> regards,
> Brian Fraser
>
> =======================================================
> Trust in God but lock your car.
>
> Brian Fraser
> Tel 27 11 871-0370
> Fax 27 11 871-0226
> email brian.fraser@macsteel.co.za
>
>
> > -----Original Message-----
> > From: Taichi Kato [SMTP:tkato@kusastro.kyoto-u.ac.jp]
> > Sent: Wednesday, September 01, 1999 4:41 PM
> > To: vsnet-chat@kusastro.kyoto-u.ac.jp
> > Subject: [vsnet-chat 2273] Strong oscillation in Nova Cir 1999?
> >
> > Strong oscillation in Nova Cir 1999?
> >
> > Upon examination of the reported data, I have noticed the nova
> may be
> > oscillating with a period close to 1 d. On Aug. 24 and 25, the nova
> > faded by nearly 1 mag within 12 hours, and recovered (not well
> covered
> > by observations). Has anyone noticed this phenomenon?
> >
> > Regards,
> > Taichi Kato
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
Return to Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
VSNET Home Page