Gliese 667 Cc is an extrasolar planet, or exoplanet, orbiting around the star Gliese 667 C which is a member of the Gliese 667 triple star system. The minimum mass of Gliese 667 Cc is about 4.39 Earth masses.
Gliese 667 Cc (also known as GJ 667Cc or HR 6426Cc) is in a nearby triple star system (Gliese 667) in the constellation Scorpius, 22.7 light years away. Gliese 667 Cc was first announced in a pre-print made public on 21 November 2011 by the European Southern Observatory'sHARPS group using the radial velocity method (Doppler method). However, the announcement of a refereed journal report came on 2 February 2012 by researchers at the University of Göttingen and the Carnegie Institution for Science.
The star Gliese 667 C hosts at least 7 planets and 3 of those, all rocky planets (including Gliese 667 Cc), are within the habitable zone. Gliese 667 Cc is located on the inner edge of the habitable zone. With the semi-major axis of only 0.1251 astronomical units, a year on Gliese 667Cc is only 28.155 days. Gliese 667Cc is said to be one of the most physically similar known exoplanets to Earth with an ESI value of 0.85. Based on GJ 667 C's bolometric luminosity, GJ 667 Cc would receive 90% of the light Earth does; however, much of that electromagnetic radiation would be in the invisible infrared light part of the spectrum. Based on black body temperature calculation, GJ 667 Cc should absorb more overall electromagnetic radiation, making it warmer (277.4 K) and placing it slightly closer to the "hot" edge of the habitable zone than Earth (254.3 K).