HAT-P-67b

HAT-P-67b is an exoplanet orbiting around the star HAT-P-67. A gas giant on a close orbit, it is a hot Jupiter with one of the largest sizes and lowest densities of any known exoplanet. With a radius of over double that of Jupiter's HAT-P-67 b is one of the largest exoplanets known to date. It also one of the least dense at approximately 0.061+0.020−0.021 grams per cubic centimeter, a density lower than that of marshmallows. It has a very close separation from its host star, taking four days and 19 hours to complete an orbit. Its host star is expanding in size as it is becoming a red giant, and in 150 to 500 million years it is expected that HAT-P-67b will be engulfed due to this expansion. An analysis of a radial velocity time series obtained at the Galileo National Telescope detected the Rossiter–McLaughlin effect and determined the projected spin-orbit angle to be 2.2 ± 0.4°. The calculated value suggests an aligned planetary orbit, indicating that the planet likely migrated to its present orbit through tidal interactions with a protoplanetary gas disk. Transits of HAT-P-67b were discovered by the Hungarian Automated Telescope Network (HATNet), using small, wide field telescopes, located at the Fred Lawrence Whipple Observatory in Arizona and at the Mauna Kea Observatory in Hawaii. Observations were made in 2005 and 2008, analysis of the obtained data revealed the periodic transits of HAT-P-67b.