Space Facts

KOI-961b, KOI-961c & KOI-961d
Miniature Planetary System

Earthdate: 2012:0116

An artist's concept of 3 planets, KOI-961b, c and d—worlds slightly smaller than Earth, but slightly more massive. Image Credit: NASA/JPL-Caltech

Three planets have been found huddled close to this dim red dwarf star. The system has been compared to Jupiter and its Galilean moons, because of the star's small mass and the closeness with which the planets orbit their parent sun.

Two of the planets are slightly more massive than Earth, while one is very slightly less massive. All three orbit so closely that likely they each are tidally locked—one face forever locked in facing their sun, while the opposite side remains forever in darkness.

Each of the planets are also likely too hot for human habitation.

System Parameters:
Name: KOI-961 (2MASS J19285255+4437096)
Apparent Magnitude: 16.12
Distance: 126 light years (38.7 parsecs) RA: 19^h 28^m 53^s
DE: +44° 37' 10"

Star:
Spectral Type: M5 V (est.)
Mass: 0.13 ☉
Radius: 0.17 ☉
Fe/H: -0.48
Temperature: 3,068 °K

Planet: KOI-961b
Discovered: 2012
Mass: 0.009 M_J (2.86 M_Earth)
Radii: 0.07 R_J (0.74 R_Earth)
Semi-major Axis: 0.0116 AU
Orbital Period: 1.2137672 days
Eccentricity: ?
Inclination: ?
Effective Temperature: ?

Planet: KOI-961c
Discovered: 2012
Mass: 0.006 M_J (1.91 M_Earth)
Radii: 0.065 R_J (0.68 R_Earth)
Semi-major Axis: 0.006 AU
Orbital Period: 0.45328509 days
Eccentricity: ?
Inclination: ?
Effective Temperature: ?

Planet: KOI-961d
Discovered: 2012
Mass: 0.003 M_J (0.95 M_Earth)
Radii: 0.05 R_J (0.54 R_Earth)
Semi-major Axis: 0.0154 AU
Orbital Period: 1.856169 days
Eccentricity: ?
Inclination: ?
Effective Temperature: ?

References:
http://exoplanet.eu/star.php?st=KOI-961, retrieved 2012:0126