WISE

Speaker: Davy Kirkpatrick

The Wide-field Infrared Survey Explorer (WISE) is a MIDEX mission to map the entire sky in four infrared bandpasses - 3.3, 4.7, 12, and 23 microns (um). The 7-month mission will use a 40-cm telescope and four-channel imager equipped with HgCdTe and Si:As 1024x1024 arrays to survey the sky from a circular orbit 500-km above the Earth. Launch is expected in November, 2009. Sensitivities will be half a million times that of COBE/DIRBE at 3.3 and 4.7 um and five hundred times that of IRAS at 12 and 23 um. WISE will be particularly sensitive to brown dwarfs cooler than those presently known since deep absorption in the methane fundamental band at 3.3 um and a predicted 5-um overluminosity will produce uniquely red 3.3-to-4.7 um colors. For a limiting volume of 25 pc, WISE will completely inventory the Solar Neighborhood for brown dwarfs as cool as 1000K. At 10 pc, the census will be complete to 500K. Assuming a field mass function with alpha=1, there could be one or more brown dwarfs warmer than 150K lying closer to the Sun than Proxima Centauri and detectable primarily at WISE wavelengths. WISE will be able to provide definitive estimates of the brown dwarf mass and luminosity functions and will enable a host of candidate targets for follow-up by the Spitzer post-cryo mission and the James Webb Space Telescope.