COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      NUMBER 618

                                      Konkoly Observatory
                                      Budapest
                                      1972 January 28


           SUSPECTED DUPLICITY OF THE Ap STAR 53 Cam


The radial velocity measures of spectra taken during different cycles
(1967-1969) did not satisfy the wellknown period of about 8 days of this
magnetic and photometric variable (Inf. Bull. Var Stars No. 388.) A new series
of spectra covering a little more than one cycle had been taken on February
1970 (dispersion 12 A/mm). The 8^d-period variations of radial velocity are
evident from Fig. 1.

                          [FIGURE 1]

These variations appear to be superimposed on a longer still unknown period
(see Fig. 2); the radial velocity of FeI lines shows a maximum positive value
between October 1967 and March 1968, becomes negative again on March 1969 and
is still negative on December 1971 (not plotted). A correction has been
allowed for, in order to reduce all the observations to phase zero, assuming
that the amplitude of the 8^d-variations remains constant.

                          [FIGURE 2]

These observations can be explained with the hypotesis of a duplicity: 53
Cam should describe an eccentric orbit around an unseen companion. The period
is probably of several years but more observations are needed to determine it.


21 st January 1972

ROSANNA FARAGGIANA
Astronomical Observatory of Trieste