COMMISSION 27 OF THE I. A. U
        INFORMATION BULLETIN ON VARIABLE STARS
                     NUMBER 249

                                Konkoly Observatory
                                Budapest
                                1968 January 16


     ON THE VARIABILITY OF THE STAR BD +56d2855


The star BD +56d2855 (9,0)=HD 240055 (9,4) (B5)=P 5699= =KZP 5612, RA
1900=22^h42^m15^s, D 1900=+56d19.'5 has hitherto often been used as comparison
star for CO Lac. Uitterdijk (1934), on inspecting photographic plates found
that on 12 September 1915 the star was by about 0.24 mag fainter than its mean
brightness. Consequently, the star BD 56d2855 has been included in the
catalogue of stars suspected of variability.

In the period 25 August 1967 to 1 October 1967, 221 observations of the star
were made at the Crimean Astrophysical Observatory (USSR) using a 64-cm
telescope equipped with a photoelectric photometer. The observations were made
in a system similar to the system B, V Johnson - Morgan. The star BD +56d2856
was used as comparison star.

The star BD +56^2855 turned out to be an eclipsing variable with elements:

J.D. 2439749,3973+6,^d3549*E
The depth of primary minimum A_1=0,30 mag
The depth of secondary minimum A_2=0,13 mag
The duration of the eclipse D=6^h20^m

in yellow. The secondary minima are lying symmetrically relative to the
primary ones. The elements in the blue colour are similar to those in yellow.

Further photoelectric observations of times of minima are desirable for a more
accurate determination of elements.


Cracow, 5 January 1968
                                   J.M. KREINER
                                   Astronomical Observatory
                                   of the Jagellonian University

References

Uitterdijk, J. BAN 7, 160, 1934 [BIBCODE 1934BAN.....7..159U ]
Wright, F. W. HA 89, 177, 1937 [BIBCODE 1937AnHar..89..171W ]
Flora, H. F. Sternberg Tr. 16, 261, 1949