[vsnet-campaign 602] RZ Leo early superhumps

["Tonny Vanmunster" <Tonny.Vanmunster@advalvas.be>]

Dear all,

I just concluded an analysis of my first 3 nights of CCD observations of RZ
Leo (Dec 21 - 23, 2000), corresponding to a total of 11.3 hours and 1134
data points. After having removed linear trends, the corresponding best
superhump period is 0.0755 +/- 0.0006 d (PDM based). This value is almost
*identical* to the published photometric period (0.0756 +/- 0.0012 d,
Mennickent et al., 1999, Astron. Astrophys. 352, 239).  Our finding
strengthens Taichi's suggestion (vsnet-alert 5452) that we are still
observing the very early stage of an WZ Sge-type dwarf nova outburst, i.e.
the 'early superhumps'. Finally, the peculiar hump profile described by
Taichi is also dominating the phase diagram of our observing set.

What an intriguing cataclysmic variable !

Kind regards,
Tonny Vanmunster
CBA Belgium Observatory

> -----Original Message-----
> From: owner-vsnet-alert@kusastro.kyoto-u.ac.jp
> [mailto:owner-vsnet-alert@kusastro.kyoto-u.ac.jp]On Behalf Of Taichi
> Kato
> Sent: Saturday 23 December 2000 11:31 AM
> To: vsnet-alert@kusastro.kyoto-u.ac.jp;
> vsnet-campaign@kusastro.kyoto-u.ac.jp
> Subject: [vsnet-alert 5452] RZ Leo superhumps: early superhumps?
>
>
> RZ Leo superhumps: early superhumps?
>
> Dear Colleagues,
>
>     We must remind that the best superhump period (P=0.0762 d) is
> extraordinally close to the photometric period (0.0756 +/- 0.0012 d,
> Mennieckent et al., 1999, Astron. Astrophys. 352, 239).  The values
> may even regarded to "agree" within their errors.
>     The observed hump profile is also peculiar in contrast to "usual"
> superhumps in SU UMa stars.  The humps show a complex structure, similar
> to "early superhumps" observed in other WZ Sge-type stars (AL Com, EG Cnc,
> HV Vir).
>     These findings may indicate that we are observing the very early stage
> of an WZ Sge-type dwarf nova, which commonly show complex "superhumps"
> whose period is close to the orbital period (see the VSNET AL Com page
> and paper for reference).
>
>     This feature may quickly decay, as in other WZ Sge-type stars, or
> develop into more distinct superhumps within several days.  Intensive
> observations at this extremely rarely met stage are of utmost importance.
>
>     The observed hump profile is available at the VSNET RZ Leo page:
>
>     http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/DNe/rzleo.html
>
>     Let's join this Christmas and New Millenium world-wide campaign!
>
> Regards,
> R. Ishioka, M. Uemura, H. Iwamatsu, T. Kato, K. Matsumoto
> at Kyoto University
> On behalf of the VSNET Collaboration team
>
>

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