1RXS J232953.9+062814: a new SU UMa star below the period minimum!

(Left: CCD image by the Kyoto team on November 4. Right: CCD image by A. Giambersio on November 7)

Outburst detection

(vsnet-alert 6830)

Visual magnitude estimate by P. Schmeer, Bischmisheim, Germany:

1RXS 232953.9+062814 (UG)
Nov. 3.926 UT, 12.5
Sequence: GSC
Instrument: 203-mm SCT
My very first observation of this CV.

232954.30 +062810.9 (2000.0) 12.7B-16.6B ug (Downes et al.)
232954.357 +062810.35 (2000.0) 15.6 15.9 (USNO-A2.0)


1RXS232953.9+062814 20011103.926 125 Scp

~66 minutes superhumps!!

(Average Light curve on November 4 and 5 by the VSNET collaboration team: M. Uemura, R. Ishioka, T. Kato, D. Starkey, T. Vanmunster, J. Pietz)

(vsnet-alert 6838)

1RXS J232953.9+062814: refined period

Dear Colleagues,

We have further analyzed the Kyoto data. We have also received new data from T. Vanmunster (cf. vsnet-alert 6837). Further analysis of the Kyoto data yielded a period of 0.046 d (the analysis in vsnet-alert 6836 seems to have been affected by a sysmatic effect, because the initial run likely missed the maximum of the first superhump). Using Vanmunster's data, we have refined the superhump period as 0.04633(2) d.

Wonderful!! We have discovered the second object that breaks the "period mimimum". The astrophysical implication is already given in vsnet-alert 6836, written by Uemura et al.

The VSNET Collaboration team chooses this object as the top priority target (WZ Sge is still a priority target; we are following the target with a second instrument). Please observe as long as possible, as we have done in our great campaign on WZ Sge!

Taichi Kato
VSNET Collaboration team

Quiescent information

(vsnet-campaign-dn 1852)

1RXS J232953.9+062814 in quiescence (submitted to IAUC)
S.V. Zharikov, G.H. Tovmassian, Observatorio Astronomico Nacional, IA UNAM (Mexico).

The 1RXS J232953.9+062814 had been classified as a cataclysmic variable by Jingyao, H. et al.(Ann. Shanghai Obs., Acad. Sin., 1998, 19, 235). Prior to the outburst detection by P. Schmeer (IAUC 7747) on November 3.926 (UT) our team observed 1RXS J232953.9+062814 in quiescence.

The CCD photometry was made with 1.5 m telescope of OAN SPM on October 25th and 26th, 2001 (JD 2452207, 2452208). Comparison with the photometric standard field of PG2213-006 revealed that the object had a mean magnitude of B=16.8 in quiescence. The object was monitored during 3.42 + 2.5 hours. It showed approximately 0.2 mag variability in B band. Period analysis based on DFT methods leads to extremely short period for the CV of about 0.0228 days. However the lightcurve shows minimas of slightly different depth. Comparing to the outburst lightcurves obtained by VSNET group (IAUC 7747) we can safely state that the lightcurve is double humped and the orbital period of the system is two times longer. The second order peak in the power spectrum at around 0.045 days is split in two equipollent values at P1=0.0446(1) and P2=0.0466(1). The duration of our observational run is not sufficient to distinguish between these two values unambiguously. However the folded data looks less scattered and shows more pronounced second shallow minimum when the P1=0.0446 days value is used. This value is also shorter by 3.7 percent than the period of assumed superhumps found by VSNET team during outburst. The lightcurve folded by this period is available at:
Meanwhile the second value of P2=0.0466 is longer than the superhump period. The reason for doublehump structure in the lightcurve is not clear yet and will need more careful investigation.

Superhump light curves

(Light curve by the Kyoto team on November 4)
(Light curve by S. Kiyota on November 6)

Spectroscpy at Gunma Astronomical Observatory

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