THE ASTRONOMICAL JOURNAL VOLUME 113, NUMBER 3, PAGE 1011 MARCH 1997 UIT: ULTRAVIOLET OBSERVATIONS OF THE SMALL MAGELLANIC CLOUD ROBERT H. CORNETT, MICHAEL R. GREASON, AND JESSE K. HILL Hughes STX Corporation, Code 681, Goddard Space Flight Center, Greenbelt, Maryland 20771 JOEL WM. PARKER Southwest Research Institute, Boulder, Colorado 80302 WILLIAM H. WALLER Hughes STX Corporation, Code 681, Goddard Space Flight Center, Greenbelt, Maryland 20771 RALPH C. BOHLIN Space Telescope Science Institute, Homewood Campus, Baltimore, Maryland 21218 KWANG-PENG CHENG Department of Physics, California State University, Fullerton, California 92634 SUSAN G. NEFF Laboratory for Astronomy and Solar Physics, Code 680, Goddard Space Flight Center, Greenbelt, Maryland 20771 ROBERT W. O'CONNELL Department of Astronomy, University of Virginia, P.O. Box 3818, Charlottesville, Virginia 22903 MORTON S. ROBERTS National Radio Astronomy Observatory, Edgemont Road, Charlottesville, Virginia 22903 ANDREW M. SMITH AND THEODORE P. STECHER Laboratory for Astronomy and Solar Physics, Code 680, Goddard Space Flight Center, Greenbelt, Maryland 20771 A mosaic of four UIT far-UV (FUV) (lambda_(eff)=1620 A) images, with derived stellar and H II region photometry, is presented for most of the Bar of the SMC. The UV morphology of the SMC's Bar shows that recent star formation there has left striking features including: (a) four concentrations of UV-bright stars spread from northeast to southwest at nearly equal (~30 arcmin=0.5 kpc) spacings; (b) one of the concentrations, near DEM 55, comprises a well-defined 8-arcmin diameter ring surrounded by a larger H alpha ring, suggestive of sequential star formation. FUV PSF photometry is obtained for 11,306 stars in the FUV images, resulting in magnitudes m(162). We present a FUV luminosity function for the SMC Bar, complete to m(162)~14.5. Detected objects are well correlated with other SMC Population I material; of 711 H alpha emission-line stars and small nebulae within the UIT fields of view, 520 are identified with FUV sources. The FUV photometry is compared with available ground-based catalogs of supergiants, yielding 191 detections of 195 supergiants with spectral type earlier than F0 in the UIT fields. The (m(162)-V) color for supergiants is a sensitive measure of spectral type. The bluest observed colors for each type agree well with colors computed from unreddened Galactic spectral atlas stars for types earlier than about A0; for later spectral types the observed SMC stars range significantly bluer, as predicted by comparison of low-metallicity and Galactic-composition models. Redder colors for some stars of all spectral types are attributed to the strong FUV extinction arising from even small amounts of SMC dust. Internal SMC reddenings are determined for all catalog stars. All stars with E(B-V)>0.15 are within regions of visible H alpha emission. FUV photometry for 42 H alpha -selected H II regions in the SMC Bar is obtained for stars and for total emission (as measured in H II-region-sized apertures). The flux-weighted average ratio of total to stellar FUV flux is 2.15; consideration of the stellar FUV luminosity function indicates that most of the excess total flux is due to scattered FUV radiation, rather than stars fainter than m(162)=14.5. Both stellar and total emission are well correlated with H alpha fluxes measured by Kennicutt and Hodge [ApJ., 306, 130 (1986)], yielding FUV/H alpha flux ratios that are consistent with models of SMC metallicity, ages from 1-5 Myr, and moderate (E(B-V)=0.0-0.1 mag) internal SMC extinction. (Copyright) 1997 American Astronomical Society.