A star containing the first transiting planet (inner planet) in a multiplanet system. Important clues about dynamics and interior dynamics can be studied in this case. In 2010 it was found to be only one of the two out of all 79 known transiting exoplanetary systems that could not support a habitable Earth-like planet, since it is too close to the habitable stars.
HAT-P-13 System Web Pages
HAT-P-13 System In the News
First Transiting Planet Found in Multiplanet System (2009)