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P. R. McCullough, J. Stys, J. Valenti (STScI), S. Fleming (Vassar), K. Janes (Boston U.), J. Heasley (U. of Hawaii)
The XO project's first objective is to find hot Jupiters transiting bright stars, i.e. V < 12, by photometry. Two XO cameras have been operating since September 2003 on the 10,000-foot Haleakala summit on Maui. Each XO camera consists of a 200-mm f/1.8 lens coupled to a 1024x1024 pixel, thinned CCD operated in drift-scan (TDI) mode. By rotating the mount at 478 arcsec/second about the declination axis while tracking at the sidereal rate in right ascension, the XO system scans repeatedly from 0 to 63 degrees of declination; each strip's width is 0.5 hours of RA. In its first year, XO has observed 6.6 percent of the sky in total, within six strips centered at RA=0, 4, 8, 12, 16, and 20 hours. Autonomously operating, XO reads out 1 billion pixels per clear night, calibrates them photometrically and astrometrically, performs aperture photometry, archives the pixel data and transmits the photometric data to STScI for further analysis. From the first year of operation, the resulting database consists of photometry of more than 100,000 stars at more than 1000 epochs per star with differential photometric precision better than 1 percent per epoch. Analysis of those light curves produces transiting-Jupiter candidates requiring detailed follow up, culminating in spectroscopy to measure radial-velocity variation in order to differentiate genuine planets from the more numerous impostors, primarily binary and multiple stars. XO is funded primarily by the Origins program of NASA.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.