Abstract AST- 9528129 Funds from this grant will be used to replace and upgrade components which limit the sensitivity of the Infrared Optical Telescope Array (IOTA). These components include the infrared beam-combining optics, the infrared detectors, the autoguiders and the data-collection computers. With these improvements the interferometer should be able to detect objects 10-20 times fainter than the present limit. In addition, by employing infrared autoguiders, it will be possible to observe true infrared sources with no visible counterparts. These changes will enable, for the first time with a near-infrared interferometer, the observations of heavily enshrouded evolved stars, Wolf-Rayet stars, planetary nebulae, emission-line stars, sources in giant molecular clouds and T Tauri stars. With an angular resolution of 0.012 arcseconds at a wavelength of 2.2 micrometers the interferometer can detect structures the size of Jupiter's orbit at the distance of the Orion star- forming regions.
