Evidence for a 581-d modulation in the pulse period of 3UO352+30

It has been shown that 3UO352 + 30 is an x-ray pulsator with a period of 13.9 min. The x-ray source has been identified with the 6 mag Be star X Per on the basis of position and interstellar absorption column data. Hutchings and others (Ap. J. 191: L101 (1974)) measured periodic shifts in the profiles of the Balmer and He I spectral lines of X Per with amplitudes of approximately 60 and 10 km/sec, respectively, which they interpreted as due to orbital motion with a period of 581 days. Some observations made from the satellite Copernicus are reported and discussed. The data are consistent with a model in which the x-ray pulse period is moderated at the same period, phase and amplitude as the optical modulation found by Hutchings if an overall downward trend in pulse period is assumed. It is recognised, however, that few data are available, and more data are required over several 580 day cycles. The effort in obtaining the data would be substantial, but should be worthwhile since it could have important implications for understanding of the X Per system. (U.K.)