(cba:news) a new and enticing erupter
Joe Patterson
jop at astro.columbia.edu
Sat Dec 13 05:34:38 EST 1997
Dear CBAers,
Enclosed is the announcement of a probable eruption in a newly discovered
CV which seems likely to be a member of one of our clubs. Jonathan got
a little photometry last week and found it near 15-16. Now it's erupted
to 12.9, it appears. So far the described behavior does not quite fit any
of the suggested classes (WZ Sge/DQ Her), but who knows, the night is
long and full of wonders. The position is in the announcement below.
Fire at will!
joe
Outburst of RX J0757.0+6306
H. Itoh (Tokyo, Japan) communicates that the cataclysmic variable
(possible SU UMa-type or DQ Her-type) RX J0757.0+6306 is undergoing an
outburst. Recent observations:
YYMMDD(UT) mag observer
971202.672 <137 (T. Watanabe)
971202.794 <146 (H. Itoh)
971203.015 <155 (G. Poyner)
971203.674 <135 (T. Watanabe)
971204.530 <133 (T. Watanabe)
971205.667 <142 (T. Watanabe)
971205.860 <131 (H. Itoh)
971212.866 129 (H. Itoh)
The following information is from the vsnet-chat log.
(http://www.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-chat/msg00662.html)
> Date: Thu, 9 Oct 1997 12:22:48 +0900 (JST)
> From: Taichi Kato <tkato at kusastro.kyoto-u.ac.jp>
> Subject: [vsnet-chat 662] RX J0757.0+6306
>
> According to "Astronomical Time Series" (ed Maoz et al. 1997, Kluwer
> Academic Press) p.195, Tovmassian et al. identified the ROSAT source
> RX J0757.0+6306 (=1RXS J075700.5+630602) as a new, ultrashort-period
> cataclysmic variable. The orbital period is 75+/-1.4 min. The optical
> spectrum shows strong hydrogen emission lines, resembling that of WZ Sge.
> Tovmassian et al. discussed in this paper the possibility of a DQ Her type.
> This star may be worth monitoring for possible future outbursts.
>
> The paper did not mention the accurate coordinates, but watching at
> the ROSAT position (07h 57m 00s.5, +63o 06' 02" 2000.0) might be sufficient.
(http://www.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-chat/msg00663.html)
> Date: Thu, 9 Oct 97 23:38:25 PDT
> From: Gaghik Tovmassian <gag at bufadora.astrosen.unam.mx>
> Subject: [vsnet-chat 663] RX J0757+6306 (Tovmassian)
>
> Dear VSNET fans,
>
> I'm readily support Taichi's call for monitoring
> RX J0757+6306. Indeed this system has all chances to
> turn into another WZ Sge system or proof to be
> the shortest period Intermediate Polar.
> Briefly what we know about this system:
> a. It is X-ray source, not much known about spectra or variability in X-rays.
> b. Optical Spectroscopy indicates CV nature with prominent accretion disk
> and hot spot.
> c. Period derived from the S-wave radial velocity variations is
> most probably 81 minutes (+/- 5 min are not excluded).
> d. The limitted photometry shows no eclipsing, high amplitude flickering
> light curves. On 4 ocassions out of 5, significant signal was recorded
> at frequency corresponding to 8.5 min oscillations.
> e. No outburst history is available at the moment.
>
> The POSS measurments of coordinates and magnitude are as follows:
> RA 07h57m01.3s DEC +63d06m01s 2000.0 16.06 (red)
>
> The identification chart is posted to VSNET separately.
> The system was reported by Tovmassian et al. in Proceedings of
> Symp. dedicated to 25th aniversary of Wise observatory
> "Astronomical Time Series" (ed Maoz et al. 1997, Kluwer Academic
> Press) p.195
> and 13th NorthAmerican Workshop on Cataclysmic Variables,
> in press.
>
> Regards, Gaghik Tovmassian
> OAN, IAUNAM, Mexico
(http://www.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-chat/msg00664.html)
> Date: Fri, 10 Oct 1997 16:25:06 +0900 (JST)
> From: Taichi Kato <tkato at kusastro.kyoto-u.ac.jp>
> Subject: [vsnet-chat 664] RX J0757+6306 chart
>
> Dear Colleagues,
>
> I have put the finding chart of RX J0757+6306 kindly provided by
> Dr. Tovmassian on the VSNET WWW/ftp. The JPEG file is at the URL:
>
> ftp://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/CVs/RXJ0757/rxj0757p63_fchart.jpg
>
> Please monitor this object, and report your (either positive or negative)
> observations to vsnet-obs.
>
> Best regards,
> Taichi Kato
Confirmation is most urgently requested; follow-up high-speed photometry
is also urgently requested.
Regards,
Taichi Kato
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