2003AJ....126.1017S

We have analyzed over 6 years of MACHO optical photometry and a smaller amount of OGLE-II data for the X-ray/Be star source RX J0058.2-7231, in the Small Magellanic Cloud. The brightness is clearly modulated with a 60 day period. During this period, the light curve shows a rapid brightening by ∼0.05 mag and a much slower decline. The amplitude of the brightening increases with wavelength, so that the system is redder in its bright phase. At R and I, there is evidence of a shallow eclipse with a duration of ∼0.1P that occurs within the bright portion of the cycle. The 60 day clock most likely represents the orbit of the X-ray source around the Be star. We suggest that the brightening may be related to changes in the Be star's disk at periastron, assuming the neutron star is in an eccentric orbit. There is some evidence that the period may be decreasing at a rate of ∼0.01 days per cycle. A single spectrum, taken during the fainter part of the light curve, shows a typical Be star, with emission lines at Hα and Hβ and absorptions at higher Balmer and He I lines. A comparison is made with the LMC X-ray/Be star system A0538-66, which has a highly eccentric orbit.