GSC 02620-00648 is a double star in the constellation Hercules. The brighter of the pair is a magnitude 12 star located approximately 1,660 light-years away. This star is about 1.18 times as massive as the Sun.[1]
In 2008 a study was undertaken of 14 stars with exoplanets that were originally discovered using the transit method through relatively small telescopes. These systems were re-examined with the 2.2M reflector telescope at the Calar Alto Observatory in Spain. This star system, along with two others, was determined to be a previously unknown binary star system. The previously unknown secondary star is a dim magnitude 14 K or M-type star separated by about 755 AU from the primary, appearing offset from the primary by about one arc second in the images. This discovery resulted in a recalculation of parameters for both the planet and the primary star.[1]
^ abcMandushev; O'Donovan, Francis T.; Charbonneau, David; Torres, Guillermo; Latham, David W.; Bakos, Gáspár Á.; Dunham, Edward W.; Sozzetti, Alessandro; Fernández, José M.; Esquerdo, Gilbert A.; Everett, Mark E.; Brown, Timothy M.; Rabus, Markus; Belmonte, Juan A.; Hillenbrand, Lynne A. (2007). "TrES-4: A Transiting Hot Jupiter of Very Low Density". The Astrophysical Journal Letters. 667 (2): L195 –L198. arXiv:0708.0834. Bibcode:2007ApJ...667L.195M. doi:10.1086/522115. S2CID6087170.