| Discovery[1] | |
|---|---|
| Discovered by | Cochran et al. |
| Discovery date | 2011 |
| Transit | |
| Orbital characteristics[1] | |
| 0.0752±0.0011 AU | |
| Inclination | 87.68±0.22° |
| Semi-amplitude | 5.1±1.9 m/s |
| Physical characteristics[1] | |
| 5.49±0.26 R🜨 | |
| Mass | 17.3±1.9 M🜨 |
Mean density | 0.59±0.07 g/cm3 |
Kepler-18c is an exoplanet that orbits Kepler-18, a star a bit bigger but less massive than the Sun, with a metallicity comparable but more than twice as old, situated around 1430 ly in the constellation of Cygnus. A planetary system made up of three bodies detected around this star on October 4, 2011 by the transit method using the Kepler space telescope.
Kepler-18c is a hot Neptune with a mass of 17.3 Earth masses, with a radius of 5.5 Earth radii and a low density of 0.6 g/cm-3.
It orbits in slightly more than 7.6 days at a distance of 0.075 AU, hence a surface equilibrium temperature of 635 °C.
References
edit- ^ a b c Cochran, William D.; Fabrycky, Daniel C.; Torres, Guillermo; Fressin, François; Désert, Jean-Michel; Ragozzine, Darin; Sasselov, Dimitar; Fortney, Jonathan J.; Rowe, Jason F.; Brugamyer, Erik J.; Bryson, Stephen T.; Carter, Joshua A.; Ciardi, David R.; Howell, Steve B.; Steffen, Jason H. (2011-11-01). "KEPLER-18b, c, AND d: A SYSTEM OF THREE PLANETS CONFIRMED BY TRANSIT TIMING VARIATIONS, LIGHT CURVE VALIDATION, WARM-SPITZER PHOTOMETRY, AND RADIAL VELOCITY MEASUREMENTS". The Astrophysical Journal Supplement Series. 197 (1): 7. doi:10.1088/0067-0049/197/1/7. ISSN 0067-0049.
Category:Hot Neptunes Category:Transiting exoplanets Category:Exoplanets discovered in 2011 Category:Cygnus (constellation)