Gliese 667 Cc

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Gliese 667 Cc
Exoplanet List of exoplanets
Gliese 667 Cc sunset.jpg
An artist’s impression of a sunset on Gliese 667 Cc as an Earth-like planet.
Parent star
Star Gliese 667C
Constellation Scorpius
Right ascension (α) 17h 18m 57.16483s
Declination (δ) −34° 59′ 23.1416″
Apparent magnitude (mV) 10.20
Mass (m) 0.31 M
Radius (r) 0.42 R
Temperature (T) 3700 K
Metallicity [Fe/H] −0.59 ± 0.10
Age 2–10 Gyr
Physical characteristics
Mass (m) 3.8[1] M
Radius (r) 1.54[1][dubious ] R
Stellar flux (F) 0.875
Temperature (T) 277.4 K (4.3 °C; 39.6 °F)
Orbital elements
Semimajor axis (a) 0.1251 ± 0.03 AU
Eccentricity (e) <0.27
Orbital period (P) 28.155 ± 0.017 d
Inclination (i) >30°
Semi-amplitude (K) 1.5 m/s
Discovery information
Discovery date 2011 (mentioned), 2012 (announced)
Discovery method Radial velocity (European Southern Observatory)
Discovery status Published refereed article

Gliese 667 Cc (also known as GJ 667Cc or HR 6426Cc) is an exoplanet 23.62 light years away. It orbits around Gliese 667 C, which is a member of the Gliese 667 triple star system, in the constellation of Scorpius.

Gliese 667 Cc was first announced in a pre-print made public on 21 November 2011 by the European Southern Observatory's High Accuracy Radial Velocity Planet Searcher (HARPS) group using the radial velocity method (Doppler method).[2] 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.[3]

Gliese 667Cc has a semi-major axis of only 0.1251 astronomical units, making its year only 28.155 days long.

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. In fact, taking into account solely the star's visual luminosity, the planet actually only receives 20% of the visible light Earth does.

Gliese 667Cc is said to be one of the most physically similar known exoplanets to Earth, with an Earth Similarity Index (ESI) value of 0.85. Gliese 667 Cc is similar in size to Earth[dubious ] with a minimum mass of about 3.8 Earth masses.[1] Based on black body temperature calculation, GJ 667 Cc should absorb similar but slightly more overall electromagnetic radiation than Earth, making it a little bit warmer (277.4 K (4.3 °C; 39.6 °F)) and consequently placing it slightly closer to the "hot" inner edge of the habitable zone than Earth (254.3 K (−18.8 °C; −1.9 °F)).[4]

Comparison to Earth[edit]

Name ESI SPH HZD HZC HZA pClass Star hClass Distance (ly) Status Year of
0N/A !Earth 1.00 0.72 -0.50 -0.31 -0.52 warm terran G mesoplanet 0 non-exoplanet prehistoric
2 Gliese 667 Cc 0.84 0.64 -0.64 -0.15 +0.21 warm terran[5] M mesoplanet 23.6[6]  Confirmed 2011

The star Gliese 667 C could host at least 7 planets and 3 of those, all rocky planets (including Gliese 667 Cc), are potentially within the habitable zone.

In fiction[edit]

Gliese 667 Cc features in the story The Audience by Sean McMullen in the June 2015 issue of Analog Science Fiction and Fact. In the Alien vs Predator franchise, Gliese 667 Cc was the first the planet to be terraformed, being done so by the Weyland Corporation in 2039.


See also[edit]


  1. ^ a b c PHL's Exoplanets Catalog - Planetary Habitability Laboratory @ UPR Arecibo
  2. ^ European Southern Observatory. Press information: The HARPS search for southern extra-solar planets. 11.24.2011. [1]
  3. ^ University of Göttingen. Presseinformation: Wissenschaftler entdecken möglicherweise bewohnbare Super-Erde - Göttinger Astrophysiker untersucht Planeten in 22 Lichtjahren Entfernung. Nr. 17/2012 - 02.02.2012. Announcement on university homepage, retrieved 2012-02-02
  4. ^ Anglada-Escudé, Guillem; et al. (2013-06-07). "A dynamically-packed planetary system around GJ 667C with three super-Earths in its habitable zone" (PDF). Astronomy & Astrophysics. arXiv:1306.6074. Bibcode:2013A&A...556A.126A. doi:10.1051/0004-6361/201321331. Retrieved 2013-06-25. 
  5. ^ List of potentially habitable exoplanets#Table
  6. ^