ROSAT OBSERVATIONS OF A NEW X-RAY TRANSIENT IN THE SMALL MAGELLANIC CLOUD

We describe ROSAT observations of a new X-ray transient and its probab le optical companion in the Small Magellanic Cloud. The transient, des ignated RX J0117.6-7330, appeared at a position similar to 5' southeas t of the X-ray pulsar, SMC X-1, in 1992 October 1-2 PSPC observations centered on the pulsar. It was detected again in a similar observation 246 days later at a counting rate diminished by a factor of 270, whic h corresponds to an average e-folding decay time of 44 days. No period ic pulsations have been detected. The average 1992 flux level would be produced by a source radiating isotropically with a luminosity of 1.6 X 10(37) (D/50 kpc)(2) ergs s(-1) in the energy range 0.2-2.5 keV. Th e 5 '' radius positional error circle includes the probable optical co unterpart in the form of a magnitude V = 14.2 star with the spectral c haracteristics of type Be.