We report results from a large Hubble Space Telescope project to observe a significant (∼34,000) ensemble of main-sequence stars in the globular cluster 47 Tucanae with a goal of defining the frequency of inner orbit, gas giant planets. Simulations based on the characteristics of the 8.3 days of time series data in the F555W and F814W Wide Field Planetary Camera 2 (WFPC2) filters show that ∼17 planets should be detected by photometric transit signals if the frequency of hot Jupiters found in the solar neighborhood is assumed to hold for 47 Tuc. The experiment provided high-quality data sufficient to detect planets. A full analysis of these WFPC2 data reveals ∼75 variables, but no light curves resulted for which a convincing interpretation as a planet could be made. The planet frequency in 47 Tuc is at least an order of magnitude below that for the solar neighborhood. The cause of the absence of close-in planets in 47 Tuc is not yet known; presumably the low metallicity and/or crowding of 47 Tuc interfered with planet formation, with orbital evolution to close-in positions, or with planet survival.

The 24.6 day eclipsing binary AI Phe contains two sharp-lined stars of comparable luminosity which undergo total eclipse, and yet are well separated. Radial velocity, photometric, and ultraviolet observations of this star have been remodeled using our improved version of the Wilson-Devinney code on the University of Calgary's Cyber 205 and Myrias SPS-2 computers. This version now has a new atmospheres option which makes use of Kurucz' model atmospheres to approximate the surface fluxes of the two stars. With the option, light curve fitting is now demonstrably improved for optical wavelengths. Rough empirical corrections result in still further improvement, with smaller discrepancies in U and u than are found using either the blackbody approximation or the previously used (Carbon-Gingerich) atmospheres option. For a specified temperature, wavelength, and logg, interpolation is performed within a table of values representing the ratio of blackbody to stellar atmosphere flux. The model atmosphere option simulates fluxes in Strömgren uvby or Johnson UAEK bandpasses, as well as in other bandpasses with widths A log X = 0.1 in the range 0.316 to 3.550 pm, and A log X = 0.05 in the UV (at 10 specified wavelengths from 0.100 to 0.282 ^m). The limb darkening of the hotter component in the far UY as it undergoes total eclipse is also investigated and compared with Kurucz models.

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