COMMISSION 27 AND 42 OF THE IAU
                   INFORMATION BULLETIN ON VARIABLE STARS
                               Number 3836

                                                         Konkoly Observatory
                                                         Budapest
                                                         4 February 1993

                                                         HU ISSN 0374 - 0676


               A FLARE EVENT ON THE A-TYPE STAR BD+47d819

A flare phenomenon was detected on the 60/90cm Schmidt telescope of Beijing
Astronomical Observatory on January 9, 1992. Kodak 103aO plates and UG2
filter were used during the observation. Each plate included 6 exposures of
each object. The exposure time for every single point was 10 minutes. By
using the CCD plate-measuring instrument, set up in the laboratory, of the
infrared astronomical group of BAO, I discovered a flare event and identified
the star with BD+47d819. It is near the open cluster a Persei. Figure 1
presents the finding chart of the star.
   The V magnitude of the star was 9.25, and B-V=0.413 (Prosser, 1992). Its
spectral type was A7 in CSI Catalog, and A5 in Fehrenbach's list (1987). The
normal U magnitude on the plates was about 10.0 mag., and the flare one was
around 8.5 mag. Figure 2 shows the photographic reproduction of the flare
event of BD+47d819. The maximum brightness appeared in the interval between
11h41m00s and 11h51m00s (U.T.).


                                [FIGURE 1]

               Figure 1. Finding chart of BD+47d819

                                [FIGURE 2]

      Figure 2. Photographic reproduction of the flare event of BD+47d819



   I shall make further observations so as to understand the characteristics of
the star better.


                                   Jun-jie WANG
                                   Beijing Astronomical Observatory,
                                   Chinese Academy of Sciences
                                   Beijing 100080
                                   China



References:

Catalog of Stellar Identifications, CDS, Strasbourg, 1979
Fehrenbach, Ch. et al., 1987, A. A. Suppl. Ser., 68, 515. [BIBCODE 1987A&AS...68..515F ]
Prosser, C. F., 1992, Astron. J., 103, 488. [BIBCODE 1992AJ....103..488P ]