on its western hemisphere. But these data were not enough on their own to decipher whether the bright spot was coming from clouds or heat. The Spitzer Space Telescope played a crucial role in answering this question. Jonathan Fortney, professor of astronomy and astrophysics at UC Santa Cruz, said: "These clouds may well be composed of rock and iron, since the planet is over ." Brice-Olivier Demory of the Massachusetts Institute of Technology noted that the oceans and continents cannot be detected, but a clear reflective signature has been detected which is interpreted as cloud. Thomas Barclay, Kepler scientist at NASA's Ames Research Center, said: "Unlike those on Earth, the cloud patterns on this planet do not seem to change much over time—it has a remarkably stable climate." Host star Kepler-7 is the largest host star of the first five planets detected by Kepler, and is situated in the Lyra constellation. The star has a radius 184% that of the Sun. Kepler-7 also has 135% the Sun's mass, and thus is larger and more massive (though less dense) than the Sun. It is slightly hotter than the Sun, as Kepler-7 has an effective temperature of . The star is near the end of its life on the main sequence. The star's metallicity is [Fe/H] = 0.11, which means that Kepler-7 has 128% the amount of iron than is detected in the Sun. Discovery In 2009, NASA's Kepler spacecraft was completing the last of tests on its photometer, the instrument it uses to detect transit events, in which a planet crosses in front of and dims its host star for a brief and roughly regular period of time. In this last test, Kepler observed stars in the Kepler Input Catalog, including Kepler-7; the preliminary light curves were sent to the Kepler science team for analysis, who chose obvious planetary companions from the bunch for follow-up at observatories. Kepler-7 was not one of these original candidates. After a resting period of 1.3 days, Kepler began a nonstop 33.5-day period in which it observed targets uninterrupted until June 15, 2009, when the collected data was downloaded and tested for false positives. Kepler-7's candidate was not found to be one of these false positives, such as an eclipsing binary star that may generate a light curve that mimics that of transiting planetary companions. Kepler-7 was then observed using Doppler spectroscopy using the Fibre-fed Echelle