The Astrophysical Journal · 1983 · 13 citations · 0 references
Natural SciencesAstronomyAstrophysicsObservational AstronomyX-ray AstronomyPulsar AstronomyX-ray BinariesAstronomical ObservationOrbital PeriodOrbital Period DeterminationPulsars In X-ray BinariesPulsation MechanismsPulsation Periods
The binary X-ray pulsar Cen X-3 was observed by the X-ray astronomy satellite Hakucho between 1981 March 21 - 26. A pulsation period of 4.8317231 ± 0.0000004 s and an orbital epoch of JD 2,444,686.44760 ± 0<SUP>d</SUP>.00005 were obtained from the pulse-timing analysis. The long-term spin-up rate in the pulsation period of Cen X-3 between 1977 and 1981 shows a decrease by a factor of 5 from that in 1975. The orbital period of 2.0871061 ± 0<SUP>d</SUP>.0000002 averaged between 1979 and 1981 exhibits a small but significant decrease. The present result confirms the trend of steady decrease of the orbital period. Possible mechanisms for the decrease of the pulsar spin-up rate and the decrease in the orbital period of Cen X-3 are discussed.