[vsnet-obs 1367] CVC 63

[tvanmuns@innet.be (Tonny Vanmunster)]

BELGIAN ASTRONOMICAL SOCIETY V.V.S. -  Working Group Variable Stars
Cataclysmic Variables Circular No.63               1995, October 18
Ed.: T. Vanmunster, Walhostraat 1A, 3401 Landen, BELGIUM
     Internet: tvanmuns@innet.be                  TEL. 32-11-831504
===================================================================

TW Tri [UGZ, 13.3p - 17.0p]
===========================

Tonny Vanmunster, Landen, Belgium has observed an outburst of this Z Cam
type dwarf nova, which is part of the Belgian CVAP. Confirmative
observations have been received from Charles Scovil (AAVSO) and Makoto
Iida (VSOLJ). C. Scovil further adds that he has a photo of the field of
TW Tri, taken on Oct 16, 1979, which shows the variable bright, perhaps
about mag. 14.2.

The following positive estimates are available :

1995 Oct 16.95  UT,  13.6  (T. Vanmunster, 0.35-m refl., seq: GSC);
     Oct 17.339 UT,  13.8  (C. Scovil, AAVSO);
     Oct 17.528 UT,  15.2  (M. Iida, 0.20-m refl.+ST-6, unfiltered);
     Oct 18.202 UT,  13.7  (C. Scovil, AAVSO, mag. between 13.6 and 13.8);

Although TW Tri is classified as a UGZ-type dwarf nova, no standstills have 
been observed yet in this system, as fas as we know. It would be interesting 
to monitor this object in more detail, especially during the current outburst 
and the decline phase.

TW Tri was last seen in outburst on August 3, 1995 (CVC 50), by Tonny Van-
munster.


PU Per [UG, 14.7p - 20:p]
=========================

The outburst of PU Per, announced in our previous circular, was a faint
and short one. The maximum magnitude (V=15.5), reported by Taichi Kato
on October 13th (CVC 62), was later revised in a VSNET message (new value 
being V=16.5).

Astrometric measurements by Makoto Iida, Nagano, Japan, on CCD images taken 
at Ouda Station, Kyoto University, Japan, have resulted in following accurate 
position of PU Per (J2000.0) : R.A.=02h42m16s.14, decl.= +35d40'46.4" 
(reference : 10 GSC stars, mean residual 0.1").

Taichi Kato, Ouda observatory, has been able to derive a rough period esti-
mate of PU Per from photometric CCD observations : "From low-amplitude hump-
like features (likely orbital humps during decline) in Oct. 13th observations, 
we have estimated a rough period of 0.058 +/- 0.002 day.  If this modulation 
actually reflects the orbital motion, this dwarf nova is suspected to be a 
ultrashort orbital period SU UMa-type dwarf nova (WZ Sge-like object or extreme 
TOAD).  The rate of decline supports this idea. The second outburst reported 
in Romano, Minello (1976, IBVS 1140) can be identified as a superoutburst."

We conclude our monitoring of the present (normal) outburst of this interes-
ting CVAP object, by listing the few available photometric observations :

-----------------------------------------------------------------------
DATE (UT)       MAGN  MS SEQ  OBSERVER        REMARKS        SOURCE
-----------------------------------------------------------------------
1995 10 13.532  16.6  CU GSC  Iida, M.        20-cm + ST-6   VSNET
1995 10 13.549  17.0  CU GSC  Iida, M.        20-cm + ST-6   VSNET
1995 10 13.714  16.5  CV GSC  Ouda team       60-cm refl.    VSNET
1995 10 14.556 [17.6  CU GSC  Iida, M.        20-cm + ST-6   VSNET
1995 10 14.624  18.4  CV GSC  Ouda team       60-cm refl.    VSNET



PV Per [UG, 14.9p - 20:p]
=========================

On October 13th, 1995, Makoto Iida, Nagano, Japan reported an outburst of 
PV Per (another CVAP object), which subsequently has been confirmed by Taichi 
Kato and the Ouda team members of Kyoto University, Japan. It turned out to 
be a very faint and short outburst, characterised by a fast decline, as the 
photometric summary below indicates :

-----------------------------------------------------------------------
DATE (UT)       MAGN  MS SEQ  OBSERVER        REMARKS        SOURCE
-----------------------------------------------------------------------
1995 10 13.528  17.0  CU GSC  Iida, M.        20-cm + ST-6   VSNET
1995 10 13.545  16.8  CU GSC  Iida, M.        20-cm + ST-6   VSNET
1995 10 13.771  17.0  CV GSC  Ouda team       60-cm refl.    VSNET
1995 10 14.548 [17.2  CU GSC  Iida, M.        20-cm + ST-6   VSNET
1995 10 14.631  18.9: CV GSC  Ouda team       60-cm refl.    VSNET

The current outburst is in sharp contract with the previously observed one 
(see CVC 58 and CVC 59), which was much brighter and lasted substantially 
longer. It therefore is very likely that the September 1995 outburst was a 
superoutburst.


CVAP UPDATE 
===========

We are once more extending the Cataclysmic Variables Alert Programme CVAP 
with a number of very interesting objects, which have been suggested to us by
various sources. Each of them deserves a close monitoring. Note that some
get bright enough to be spotted with relatively small telescopes.

New CVAP objects are :

  VARIABLE    RA           DECL         TYPE  MAG_RANGE       REMARKS 
  NAME            [2000.0]                    MAX      MIN 
  --------    ------------------------  ----  --------------  ------- 
  NSV 786     02 22 21.1   +78 53 36.   UG?   12p     14p     [1,4,5]  
  NSV 2872    06 14 10.6   +45 30 12.   UG?   11.2p   14.5p   [1,3,4,5]
  NSV 4838    10 23 18.7   +44 05 00.   UG?   14.5p   16.5p   [1,5] 
  NSV 5543    12 18 38.4   +40 01 39.   UG?   12p    [14p     [1,5] 
  V630 CYG    21 34 59.31  +40 40 17.4  ugSU: 13.4p   17.2p   [2]  
  GD 552      22 50 39.75  +63 28 38.1  NL/UG?    16.5v       [2,5]  

[1] Position from GCVS
[2] Position from Downes and Shara (1993)
[3] Might be not a CV
[4] No references in Simbad Catalog
[5] No visual observations listed in Vanmunster and Howell (1995)

Finding charts and GSC-based sequences have been prepared for all new objects
(except for V630 Cyg, for which we advise to use the AAVSO chart) and are 
available to observers upon simple request. 


Tonny Vanmunster

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