We present observations of a series of 10 outbursts of pulsed hard X-ray flux from the transient 10.6 mHz accreting pulsar GS 1843-02 , using the Burst and Transient Source Experiment on the Compton Gamma Ray Observatory .
These outbursts occurred regularly every 242 days , coincident with the ephemeris of the periodic transient GRO J1849-03 ( [ Zhang et al .
1996 ] ) ) , which has recently been identified with the SAS 3 source 2S 1845-024 ( [ Soffitta et al .
1998 ] ) .
Our pulsed detection provides the first clear identification of GS 1843-02 with 2S 1845-024 .
We present a pulse timing analysis which shows that the 2S 1845-024 outbursts occur near the periastron passage of the neutron star ’ s highly eccentric ( e = 0.88 \pm 0.01 ) 242.18 \pm 0.01 day period binary orbit about a high mass ( M _ { c } > 7 M _ { \odot } ) companion .
The orbit and transient outburst pattern strongly suggest the pulsar is in a binary system with a Be star .
Our observations show a long-term spin-up trend , with most of the spin-up occurring during the outbursts .
From the measured spin-up rates and inferred luminosities we conclude that an accretion disk is present during the outbursts .