Kepler-12b

Kepler-12b is a hot Jupiter that orbits G-type star Kepler-12 some away. The planet has an anomalously large radius that could not be explained by standard models at the time of its discovery, almost 1.7 times Jupiter's size while being 0.4 times Jupiter's mass. The planet was detected by the Kepler spacecraft, a NASA project searching for planets that transit (cross in front of) their host stars. The discovery paper was published on September 5, 2011.

==Discovery== NASA's Kepler spacecraft continuously observes a region of the night sky, searching for signs of transiting planets. While orbiting their host stars, such transiting planets cross in front of host stars as seen from Earth. The slight and periodic dimming in the star's brightness is used to determine whether or not the dimming was caused by a planet and not by a false positive. Analysis of Kepler's early data yielded evidence of a transit signal around a star designated as KIC 11804465, later known as Kepler-12. The transit signal was designated KOI-20. 200px|left|thumb|The Keck Observatory collected observations to prove that Kepler-12b's signal was not actually caused by an eclipsing binary. The Kepler Follow-up Program (KFOP) worked to verify the existence of the planet. KFOP used the W.M. Keck Observatory's Keck I telescope to prove that Kepler-12 was not an eclipsing binary star (a possible false positive that mimics the transit signal). The WIYN Observatory, which was used for speckle imaging, supported Keck's findings and verified that the signal caused by KOI-20 was not caused by a nearby background star's interference. Adaptive optics imaging in the near-infrared was obtained on September 9, 2009 with the Palomar Observatory's PHARO camera on the Hale Telescope confirmed both the WIYN and Keck findings.