RECURRENCE TIMES AND PERIODICITIES IN 4U-1608-52 AS OBSERVED BY VELA-5B

We report on the Vela 5B 10 year history of the soft X-ray transient 4 U 1608-52, and on the characteristics of its soft X-ray outbursts. The Vela 5B satellite observed the four known outbursts in 1975, 1977, an d 1979, and four new outbursts in 1970 and 1971, altering the recurren ce pattern of outbursts from this source. One of the 1970 outbursts is symmetric in its intensity profile, while the two outbursts in 1971 h ave short exponential profiles separated by 80 days. Despite suggestiv e recurrence periods of similar to 85 and similar to 150 days evident in the time intervals between the outbursts, there is no single statis tically significant recurrence time on which the outbursts recur consi stently. In the 1970 symmetric event, there is evidence for a period o f either 4.10 or 5.19 days. Drawing upon the analogy with SU Ursa Majo ris dwarf novae, we suggest that the short period is orbital and any l onger period would be associated with a precession period of the accre tion disk.