No.32

Oct. 1998

ISSN 0917-2211

Variable Star Bulletin
Outburst of RX J0575.0+6306
Tsutomu Watanabe
117 Shirao dormitory , 1414 Oonakazato , Shizuoka , 418-0044 Japan
E-mail : jcc00212@nifty.ne.jp
Received 27 Jul 1998

1Observations

The ROSAT source RX J0757.0+6306 was optically identi¯ed with a cataclysmic variable located at R.A. 07h 57m 01.3s Dec. +63 ゜ 06' 01" (J2000.0) ,having a 75 min orbital period , and showing a spectrum resembling that of WZ
Sge (Tovmassian et al. 1997, 1998a). VSOLJ members carried out 86 visual observations between 1997 Oct. and 1998 Jun.: T.Watanabe (58 obs.) , H.Itoh (26obs.) , S.Takahashi (1 obs.) and M.Hiraga (1 obs.). The Light curve is shownin Figure 1. One short outburst was detected on 1997 Dec 12 at a magnitudeof 12.9 by H.Itoh. Subsequent con¯rmation by other observers was prevented
by the waxing moonlight and the low transparency characteristic to the season.
He later con¯rmed observed position was truly correct. The duration the object
was brighter than 13.0 magnitude is shorter than 3 days. Observation data near
the outburst are listed in Table 1. Considering the magnitude and the duration, the outburst seems to be a normal outburst.

Figure 1 : Light curve of RX J0757.0+6306 between 1997 Oct. and 1998 Jun.

1

Table 1. Observation data near the outburst
Date(UT)
Mag. ¤ Observer
19971205.860<131Ioh19971210.663<130Wnt
19971212.866
129
Ioh19971213.549<123Ioh19971213.549<123Ioh19971213.578<130Ths
19971213.669<131Ioh19971220.797<135Wnt¤2The pre¯x < indicates the upper limit ( the variable was not seen )code: Ioh (H. Ito), Ths (S. Takahashi), Wnt (T. Watanabe)

Acknowledgments

I wish to thank Dr.Taichi Kato ( Kyoto University ) for his helpful suggestions
and reading the manuscript.

3Remarks

This outburst detection was announced in [vsnet-obs 8928], which was referred
to and discussed in Tovmassian et al. (1998b).

References[1] Tovmassian G. et al , "Astronomical Time Series" (ed Maoz et al. Kluwer
Academic Press) p.195 (1997)[2] Tovmassian G.et al , 13th NorthAmerican Workshop on Cataclysmic Variables , in press (1998a)[3] Kato T. , "VS observations by Ioh (Dec. 10-12)" , vsnet-obs 8928 (1997)[4] Tovmassian G. et al. , Astron. Astrophys. 335, 227 (1998b)

Light Curve of SBS1017+533
Tsutomu Watanabe
117 Shirao dormitory , 1414 Oonakazato , Shizuoka , 418-0044 Japan
E-mail : jcc00212@nifty.ne.jp
Received 4 Aug 1998

1Observations

SBS1017+533 (R.A.10h 20m 30s Dec.+53 ゜ 02' 07" (2000)) is a cataclysmic
variable discovered by the SBS servey (Balayan 1997). The star was identi¯edwith the ROSAT X-ray source RX J1020.4+5304 (Bade N. 1998 ,independently Kato 1998 and Garnavich 1998) The ¯rst outburst was discoveredby Garnavich (1998) on 1998 Jan. 27.5. Superhumps with a period of 0.069
d were detected (Vanmunster 1998a, Nogami 1998), con¯rming the UGSU
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Table 1. Magnitude estimates of SBS1017+533.
Date(UT)
19980203.643
19980203.643
19980215.646
19980217.656
19980301.691
19980303.653
19980315.556
19980316.596¤Mag. ¤
130
130
<132<137<145<143135<138

Observer
WntWntWnt
Wnt
Wnt
Wnt
Wnt
Wnt

Date(UT)
19980322.689
19980403.617
19980426.544
19980428.617
19980428.701
19980429.515
19980504.596
19980505.526

Mag. ¤<132
<145
<151
127
127
138
<143
<137

Observer
Mhh
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt
Wnt

Date(UT)
19980520.528
19980522.600
19980523.501
19980530.549
19980615.597
19980620.533

code: Mhh (H. Maehara), Wnt (T. Watanabe)
The pre¯x < indicates the upper limit ( the variable was not seen )type. After this outburst, VSOLJ members detected additional 2 normaloutbursts (total 3 outbursts) by visual observations between 1998 Feb.and
1998 Jun. The light curve is shownin Figure 1. and the original data are
given in Table 1.Both normal outbursts were con¯rmed by other observers(Kinunnen 1998 , Poy ner 1998 and Vanmunster 1998b) As shown in Figure
1, the mean cycle length of outbursts is about 45 days. Further obsevations
are strongly encouraged.

Figure 1 : Light curve of SBS1017+533.

2

Acknowledgments

I wish to thank Dr.Taichi Kato (Kyoto University) for his helpful suggestions
and reading the manuscript.

References[1] Bade N. et al. , Astronomy and Astrophysics Supplement 127, 145 (1998)[2] Balayan S. K., Astrophysics 40, 101 (1997)[3] Garnavich P., VSNET-alert 1441 (1998)[4] Kato T., VSNET 1133 (1998)[5] Kinunnen T., VSNET-obs 10331 (1998)
3Mag. ¤
<125<143<145<143<135<143Observer
Mhh
Wnt
Wnt
Wnt
Wnt
Wnt

[6] Nogami D., VSNET-alert 1452 (1998)[7] Poyner G., VSNET-obs 11555 (1998)[8] Vanmunster T., Cataclysmic Variables Circular 161 (1998a)[9] Vanmunster T., et al., VSNET-alert 1726 (1998b)

Variable Star Observers League in Japan
National Science Museum
Ueno Park Taito-ku Tokyo 110 Japan
Editor
Keiichi Saijo
Assistant-editor
Seiichi Sakuma
Sta®
Makoto Watanabe
Masahiko Momose
Seiichiro Kiyota
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