Kepler-42c

Kepler-42 c, previously KOI-961.02 then KOI-961 c, is an exoplanet orbiting Kepler-42, a star located about 131 light-years (40 pc) from the Solar System, in the constellation of Cygnus. A planetary system of at least three exoplanets with sizes between Mars and Venus has been detected around this red dwarf on January 11, 2012 by the method of transits with the help of the space telescope Kepler.

Kepler-42 c

Sizes of Earth-like planets, including Mars, Kepler-42c (KOI-961.02), Kepler-20e, Kepler-20f and Earth.
Discovery
Discovered by	Philip S. Muirhead et al.[1]
Discovery site	In space
Discovery date	January 11, 2012
Detection method	Transit (Kepler)
Orbital characteristics
Semi-major axis	~ 0.0060 AU
Orbital period	0.45328509 ± 9.7×10^−7[1] d
Inclination	85.06^+0.15 −0.16
Star	Kepler-42
Physical characteristics
Mean radius	0.73 ± 0.20[1] R⊕
Temperature	720 ± 73[1]

Kepler-42 c is a planet with a radius 0.73 times that of Earth. It orbits its star in a little less than 11 hours at about 0.006 AU of its host star and has an average equilibrium temperature of about 445°C (833°F). Due to the temperature, it is not suitable for life.

It is tidally locked in a synchronous rotation. Thus, it makes one complete rotation each time it completes an orbit. As a result, there is an eternal day side and a permanent night side.

References

1. Philip S. Muirhead, John Asher Johnson, Kevin Apps, Joshua A. Carter, Timothy D. Morton, Daniel C. Fabrycky, J. Sebastian Pineda, Michael Bottom, Barbara Rojas-Ayala, Everett Schlawin, Katherine Hamren, Kevin R. Covey, Justin R. Crepp, Keivan G. Stassun, Joshua Pepper, Leslie Hebb, Evan N. Kirby, Andrew W. Howard, Howard T. Isaacson, Geoffrey W. Marcy, David Levitan, Tanio Diaz-Santos, Lee Armus, James P. Lloyd, « Characterizing the Cool KOIs III. KOI-961: A Small Star with Large Proper Motion and Three Small Planets » accepté pour publication dans The Astrophysical Journal – arXiv:1201.2189v1.