COMMISSION 27 OF THE I. A. U.
            INFORMATION BULLETIN ON VARIABLE STARS
                         Number 3371    

                                             Konkoly Observatory
                                             Budapest
                                             8 September 1989

                                             HU ISSN 0374 - 0676


           NEW OUTBURST OF THE SYMBIOTIC STAR CH Cyg


The gradual decrease of the star's brightness in the U-filter down to values of
about 11 mag and the vanishing of its rapid fluctuations in the U, B, V
filters, were observed from 1986 to September 1988. These facts were
interpreted as a photometric evidence of the end of the active phase of CH Cyg
(Skopal, 1988, 1989).

New photometric U, B, V observations were carried out at the Skalnate Pleso
Observatory with a single-channel photoelectric photometer installed in the
Cassegrain focus of the 0.6/7.5 m telescope from September 1988 (JD 2447424) to
August 1989 (JD 2447760). The data of the comparison (HD 184 786) and check
(HD 184960) star were published by Chochol et al. (1984). The average values
of the U and V magnitudes during one night are shown in Figure 1.

The changes of the star's brightness in the U-filter photometrically beat
reflect the activity of this symbiotic star. The U magnitude reached the value
of 11.1 mag from September 1988 till November 1988. No rapid changes were
observed in that period. From December 17, 1988 to April 25, 1989, a small
increase of about 0.2-0.5 mag in the U-filter was indicated. Its sudden
increasing from April 25 (10.8 mag) till the recent observation in August 22
(8.8 mag) is observed. The U-B and B-V colors decreased from ~1.6 and ~1.8 to
~0.4 and ~1.4 respectively. This rapid change of the U magnitude, ~2 mag/4
months, can be classified as a new outburst of this symbiotic star. Moreover,
the rapid fluctuations of the star's brightness in the U-filter were observed
again. The V magnitude is still running approximately between 6.7 mag and 7.9
mag, and its changes have not been influenced yet by increasing of the blue
continuum.


                                 [FIGURE 1]

 Figure 1. The U and V light curve of CH Cyg in 1986 - August 1989. 
 Sudden increasing of the star's brightness in the U filter is observed in 
 May - August 1989. [dot] - U, x - V data taken from literature; [circle], 
 + - observations carried out at the Skalnate Pleso Observatory: Skopal 
 (1987, 1989) and from JD 2447420 this paper.



A. SKOPAL
Astronomical Institute
Slovak Academy of Sciences,
059 60 Tatranska Lomnica,
Czechoslovakia

References:

Chochol, D., Hric, L., Skopal, A., Papousek, J.: 1984, Contr. Astron. Obs.
   Skalnate Pleso 12, 261 [BIBCODE 1984CoSka..12..261C ]
Skopal, A.: 1987, Contr. Astron. Obs. Skalnate Pleso 16, 69. [BIBCODE 1987CoSka..16...69S ]
Skopal, A.: 1988, Inf. Bull. on Variable Stars No. 3245.
Skopal, A.: 1989, Contr. Astron. Obs. Skalnate Pleso 18, 31. [BIBCODE 1989CoSka..18...31S ]