Kepler-442b
Kepler-442b (also known by its Kepler object of interest designation KOI-4742.01) is a confirmed near-Earth-sized exoplanet, likely rocky, orbiting within the habitable zone of the K-type main-sequence star Kepler-442, about 1,206 light-years (370 pc) from Earth in the constellation of Lyra.
Approximate size comparison of Kepler-442b (left) with Earth | |
| Discovery | |
|---|---|
| Discovered by | Kepler spacecraft |
| Discovery date | 6 January 2015 |
Detection method | Transit |
| Orbital characteristics | |
Semi-major axis | 0.409+0.209 −0.060 AU |
| Eccentricity | 0.04+0.08 −0.04 |
Orbital period (sidereal) | 112.3053+0.0024 −0.0028 d |
| Inclination | 89.94+0.06 −0.12 |
| Star | Kepler-442 (KOI-4742) |
| Physical characteristics | |
Mean radius | 1.34+0.11 −0.18 R🜨 |
| Mass | 2.3+5.9 −1.3 ME |
| Temperature | Teq: 233 K (−40 °C; −40 °F) |
The planet orbits its host star at a distance of about 0.409 AU (61.2 million km; 38.0 million mi) with an orbital period of roughly 112.3 days. It has a mass of around 2.3 and has a radius of about 1.34 times that of Earth. It is one of the more promising candidates for potential habitability, as its parent star is at least 40% less massive than the Sun – thus, it can have a lifespan of about 30 billion years.
The planet was discovered by NASA's Kepler spacecraft using the transit method, in which it measures the dimming effect that a planet causes as it crosses in front of its star. NASA announced the confirmation of the exoplanet on 6 January 2015.