[vsnet-obs 2218] CVC 83 (GK Per, AQ CMi, SX LMi)

[Tonny Vanmunster <tvanmuns@innet.be>]

BELGIAN ASTRONOMICAL SOCIETY V.V.S. -  Working Group Variable Stars
Cataclysmic Variables Circular No.83              1996, February 26
Ed.: T. Vanmunster, Walhostraat 1A, 3401 Landen, BELGIUM
     Internet: tvanmuns@innet.be                  TEL. 32-11-831504
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         The CATACLYSMIC VARIABLES Home Page: http://vsnet.cv.psi.edu
===================================================================

GK Per [NA/DQ, 0.2v - 13.0V]
============================

This object is part of the TA/BAAVSS Recurrent Objects Programme, and
is very likely entering a (minor?) outburst phase, as indicated by the 
observations below :

1996 Feb. 21.801 UT, 13.2  (G. Poyner, Birmingham, UK);
     Feb. 21.824 UT, 13.0  (E. Broens, Mol, Belgium);
     Feb. 21.904 UT, 13.3  (T. Vanmunster, Landen, Belgium);
     Feb. 22.510 UT, 13.2  (N. Makiguchi, Japan);
     Feb. 22.822 UT, 13.2  (J. Pietz, Erftstadts, Germany);
     Feb. 23.828 UT, 12.9  (P. Schmeer, Bischmisheim, Germany);
     Feb. 23.833 UT, 13.0  (K. G. Andersson, Sweden);
     Feb. 23.840 UT, 13.1  (M. Westlund, Sweden);
     Feb. 23.873 UT, 13.1  (J. Pietz);
     Feb. 23.881 UT, 13.1  (J. Pietz);
     Feb. 24.515 UT, 13.0  (M. Nakatani, Japan);
     Feb. 25.819 UT, 12.7  (P. Schmeer);
     Feb. 26.054 UT, 12.4  (J. Mc Kenna, UDA);
     Feb. 26.463 UT, 12.4  (Ouda Team, CCD+V filter);
     Feb. 26.781 UT, 12.4  (P. Schmeer);

According to the "Outburst Activity Data on Selected Cataclysmic Vari-
ables", GK Per underwent its previous minor outburst in July 1992, when 
it reached mag. 10.1. In 'Cataclysmic Variable Stars', B. Warner remarks,
upon discussing the outburst characteristics of GK Per as an intermediate 
polar : "GK Per has a long orbital period (2d) and therefore has adequate 
room for a large accretion disc ... The DN outbursts of GK Per show a 
very slow rise (ca. 35d) to maximum ... The spectroscopic behaviour during 
outburst differs from ordinary DN : all lines remain strongly in emission."

It is evident that multi-wavelength follow-up observations are most 
desirable.


AQ CMi [UGSU, 14.5p - <16.5p]
=============================

The AQ CMi eruption has been well-covered and resulted in some very
interesting outburst data, demystifying this peculiar object a little.
We have prepared a light curve of the present outburst, on the basis
of all available photometric observations. You may consult it on the 
Cataclysmic Variables Home Page.

Joe Patterson, Department of Astronomy, Columbia University reports
a superhump period of 95.2+-0.2 min, based on observations with the
CTIO 1-m telescope. He further adds : "Probably the dwarf nova has 
returned to near minimum.  Continued vigilance is very desirable to see if 
the star "echoes" within a few days.  Also, the star is so little-known 
that there is still no basic information about the recurrence time of
normal and super-maxima, so observation over the next few months is quite 
important."


SX LMi [NL/DQ:, 16B]
====================

We have decided to add this highly interesting cataclysmic variable
to the CVAP. Observers are strongly encouraged to include the object
in their observation programme, and to alert us in case of an out-
burst (several professional astronomers have expressed strong interest 
in this variable). For the convenience of our observers, we have
prepared a finder chart and sequence, which may be obtained on the
Cataclsymic Variables Home Page.

This is the list of outbursts of SX LMi, as they appear in the 
"Outburst Activity Database" :

1992.1025       48921   13.6    RoboScope, superoutburst?       
1993.1211       49333   14.5    RoboScope, related to 48921 ?
1994.0114       49367   15.1    RoboScope                       
1994.0331       49443   13.8    RoboScope, superoutburst?       
1994.1213       49699   13.4    RoboScope, superoutburst?       
1995.0131       49749   14.4    RoboScope                       
1995.0405       49815   13.6    Pietz                           

Remark that there has been NO outburst observation since April of 
last year !

The team of T. Kato, Ouda Station, Japan made photometric observations 
during the December 1994 outburst of SX LMi. They found a superhump 
period of approx. 100 min, and S. Howell, Planetary Science Institute,
AZ once announced an orbital period of ca. 90 min.


Tonny Vanmunster

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