The eclipsing dwarf nova S10932 in outburst!

On the opening night of 1996, the sky at Ouda Station was getting perfectly clear; while trying to make a calibrated chart of S10932, recently introduced as our prime targets of eclipsing CVs. The telescope slewed. "This makes my first look at this field -- what a sparse field ..."

(vsnet-alert 306, T. Kato)

CCD observation at Ouda Station seems to show the eclipsing dwarf nova S10932 in outburst at V~13.5 on Jan. 1.83 UT. Since we have no precise finding chart and lack of suitable GSC stars in the CCD field, independent confirmation is very strongly urged.

                   R.A. (2000.0) Decl.     type    range
    S10932      12 39 32.1   +21 08 06    UG:+E 13.4    18.5p

from [vsnet 133] call for observations of S10932

In IBVS No. 4182 (Wenzel and Schwartz), S10932 (=RX J1239.5+2108) has been announced to be a new eclipsing cataclysmic variable (likely a dwarf nova) below the period gap. Intensive monitor for outbursts would be interesting as the third member of eclipsing SU UMa (candidates) in the northern hemisphere (the other two are HT Cas and DV UMa).

     Position and the elements are as follows:

     12h 39m 32s.1
     +21o 08' 06"  (J2000.0)


   (from Richter 1994, poster presented at Padova CV Conference)

According to IBVS No. 4182, the mid-eclipse times are given as:

    Min.(hel.) = JD 2449486.4821 + 0.08703 E

Taichi Kato

Wow! eclipse just caught!

(vsnet-alert 307, T. Kato)

Preliminary analysis of CCD observations at Ouda Station confirms the outburst of S10932 accompanied by a deep eclipse. The object is ~2.1 mag brighter in V than GSC 15.2 (12h39m24s.02 +21o14'14".8 J2000.0) outside eclipses. An eclipse was fortunately caught centered at JD (geocentric) 2450084.34935, with a depth of ~1.3 mag and a duration of 12min. The profile of the eclipse is remarkably similar to those observed in HT Cas during the recent outburst, but with some hint of totality lasting 1-2 min.

outburst image (object at the right bottom)

outside eclipse

in eclipse


Taichi Kato & Ouda team

Rapid decline ...

(vsnet-alert 309, T. Kato)

V-band CCD observations at Ouda Station (Kyoto University) indicates that S10932 was fading rapidly on Jan. 2. An approximate magnitude outside eclipses was V=14.8 on Jan. 2.89, while the object was observed at around V=14.0 on Jan. 1.83-1.89 (magnitudes were calibrated using GO Com and AL Com secondary standards). This fact suggests that the present outburst of S10932 is a normal one, which is also supported by the lack of apparent superhumps.

VSNET charts of S10932 (in PostScript)

enlarged chart

S10932 east field

Eclipse times from Soneeberg plates and new CCD measurements

(vsnet-alert 310, Peter Kroll and Gerold A. Richter)

The current outburst of this star led us to (re)analyse CCD observations made at Sonneberg Observatory with a 60-cm-Cassegrain telescope from 1994-May-11 to 1996-Jan-04.

Eclipsing times published in "Wenzel, Richter, Luthardt, Schwartz: IBVS 4182" are now improved. We have listed all eclipsing times based on CCD measurements and in addition four minima from the Sonneberg Sky Patrol (SSP):

Instr.  HJD 2400000+    E       O-C (d)

SSP     41798.443       -88329  +0.000261
SSP     45814.407       -42189  -0.000097
SSP     46910.398       -29597  -0.000064
SSP     47265.515       -25517  -0.000849
CCD     49484.39297     -24     +0.000238
CCD     49484.48022     -23     +0.000449
CCD     49486.48240     0       +0.000740     
CCD     49488.39654     22      +0.000029
CCD     49488.48385     23      +0.000301
CCD     49511.46160     287     -0.000159
CCD     49748.46836     3010    +0.000295
CCD     49758.47767     3125    +0.000158
CCD     49771.44638     3274    +0.000106
CCD     49771.53334     3275    +0.000027
CCD     49787.37358     3457    -0.000772
CCD     49787.46124     3458    -0.000150
CCD     49787.54842     3459    -0.000009
CCD     49787.63531     3460    -0.000158
CCD     49788.41972:    3469    +0.000904:
CCD     49788.50576     3470    -0.000094
CCD     49788.59273     3471    -0.000163
CCD     50087.57025     6906    -0.000484
CCD     50087.65795     6907    +0.000178

Using these minima times (except uncertain minimum 3469), which are distributed over more than 20 years, and the eclipsing times published in "vsnet-alert 308" and "309" by Taichi Kato & Ouda team we could derive the following ephemerides:

        Min (HJD) = J.D. 2449486.48166 + 0.0870386727 * E
Our observations of 96-Jan-04/05 (E 6906 and E 6907) show the ecplises with an amplitude of about 4.4 mag (R band)!

Peter Kroll and Gerold A. Richter 96-Jan-09
Sonneberg Observatory, Germany

Light Curve

Eclipse light curve

Eclipse light curve on Jan. 2 (Ouda Station)

Revised ephemeris

* Ephemeris

V-band VSNET chart

(area immediately east and S10932 nearby)

Later outbursts

The 1996 Mar. outburst

The 1996 Jan. outburst (Japanese text)

The 1997 Apr. outburst

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