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[vsnet-obs 2133] CVC 82 (FS Aur, AQ CMi)

BELGIAN ASTRONOMICAL SOCIETY V.V.S. -  Working Group Variable Stars
Cataclysmic Variables Circular No.82              1996, February 17
Ed.: T. Vanmunster, Walhostraat 1A, 3401 Landen, BELGIUM
     Internet: tvanmuns@innet.be                  TEL. 32-11-831504
     --------------------------------------------------------------
         The CATACLYSMIC VARIABLES Home Page: http://vsnet.cv.psi.edu
===================================================================

FS Aur [UGZ:, 14.4v - 16.2v]
============================

Gary Poyner, Birmingham, UK reports his outburst detection of this CVAP
object. Confirmation came from Tonny Vanmunster, Landen, Belgium. We
have following observations available :

1996 Feb. 13.920 UT,  15.5 (G. Poyner, 0.40-m refl.);
     Feb. 14.926 UT, [14.9 (G. Poyner);
     Feb. 16.971 UT,  15.2 (T. Vanmunster, 0.35-m refl., seq: VSOLJ);

According to our records, the object was last seen in outburst on 1995 
December 15, when it reached mag. 14.4 (CVC 74).

Given the rather frequent outbursts of this object and the relatively good
coverage (even during quiescence), we have decided to drop this object from
the CVAP.


AQ CMi [UG:, 14.5p - <16.5p]
============================

Further to the outburst announcement in CVC 81, follow-up observations
have been reported as follows :

-----------------------------------------------------------------------
DATE (UT)       MAGN   MS SEQ  OBSERVER        REMARKS        SOURCE
-----------------------------------------------------------------------
1996 02 04.962 [13.8   mv      Poyner, G.                     CVC 81
1996 02 10.975  14.4   mv      Pietz, J.                      CVC 81
1996 02 11.415  14.9   CU      Iida, M.        20-cm refl.+ST-6 CVC 81
1996 02 12.425  15.3   CU      Iida, M.        20-cm refl.+ST-6 VSNET
1996 02 12.556  14.6   CV      Nogami & Ouda Team             VSNET
1996 02 13.462  14.6   mv      Nelson, P.                     VSNET
1996 02 13.895  15.3   mv      Poyner, G.                     VSNET
1996 02 14.462  14.6   mv      Nelson, P.                     VSNET
1996 02 14.910  15.2   mv      Poyner, G.                     VSNET
1996 02 15.558 [14.0   mv      Takahashi, S.                  VSNET
1996 02 15.824  15.1   CU      Candela & Decomble             VSNET
1996 02 16.936 [14.1   mv      Vanmunster, T.                 VVS


The detection of superhumps in AQ CMi through photoelectric photometry was
first announced by Joe Patterson, Department of Astronomy, Columbia Univer-
sity : "V-band photoelectric photometry by A. Shambrook with the CTIO 1 m 
telescope shows superhumps in the light curve of this recently-erupted dwarf 
nova.  Timings on February 12 and 13 indicate a period of 95.9+-0.3 minutes.  
The amplitude (0.17 mag peak-to-trough) and waveform (fast rise, slow decline) 
are normal for SU UMa stars in early decline from a superoutburst. On February 
13 the star was at V=14.5."

Patterson further requested a close monitoring of AQ CMi for a possible
"echo" signature : "CCD observers can perhaps follow this star as it gets 
considerably fainter, and look for the "echo" signature (after a sharp fading 
to near quiescence) that is often seen in this class of dwarf novae. That would 
be awfully interesting, as would its (certifiable) absence."

The Japanese team of Ouda Station at Kyoto University independently detected
superhumps in AQ CMi, and were able to derive a superhump period which is very
close to the value reported by Patterson : "We observed AQ CMi for 6 hours
at Ouda 
Station on Feb. 12, using a 60-cm refl. + CCD + Johnson V filter.  Our
observation 
independently revealed superhumps with an apmlitude of about 0.2 mag.  A
preliminary 
period analysis gives 0.06625 d (= 95.4 min) as the best estimated superhump
period, 
which agrees with the one given by Patterson et al."


Tonny Vanmunster