A New Be-star/X-ray Pulsar in the LMC

Previous abstract Next abstract

Session 102 -- X-Ray Variables, Binaries and Transients
Display presentation, Thursday, 12, 1995, 9:20am - 6:30pm

[102.11] A New Be-star/X-ray Pulsar in the LMC

T.K. McGrath, P.C. Schmidtke, A.P. Cowley, A.L. Anderson (ASU)

Among the known high-mass X-ray binaries (HMXB) the optical primary stars are about equally divided between early-type supergiants and Be stars. Aproximately two dozen Be-type X-ray sources have been identified in the Galactic plane and Magellanic Clouds. In twelve of these systems X-ray pulsations have been detected, with pulse periods ranging from 0.069 sec (for 0535$-$668) to 835 sec (for X Per). Corbet (1984) was the first to show that the pulse and orbital periods in the Be-star/X-ray pulsars are strongly correlated. Only two such Be-star systems are presently known in the Magellanic Clouds -- the 16-day transient 0535$-$668 in the LMC (Skinner et al. 1982) and RX J0059.2$-$7138 in the SMC (Hughes 1994). Recent ROSAT observations of the LMC Be-star source CAL E ($=$RX J0502.9$-$6626) reveal X-ray pulses with a period of 4.0635 sec. Based on this pulsation period, it is expected that the orbital period may be near 30 days, which is consistent with limited spectroscopic studies which have been carried out (Crampton et al. 1985). Further optical and X-ray observations should be initiated to determine orbital elements for CAL E.

Thursday program listing