K2-146 b
K2-146 b is a super-Earth orbiting K2-146 in the constellation Cancer. It lies about 259 light-years from Earth and was discovered in 2018 using the transit method.
How Big Is K2-146 b?
K2-146 b has a radius of 2.05 times that of Earth. Its mass is 5.8 times that of Earth, giving it a density of 3.69 g/cm³ — between that of rocky and gaseous planets.
Is K2-146 b in the Habitable Zone?
The position of K2-146 b relative to the habitable zone of K2-146 cannot be precisely determined from the available orbital data.
Habitable zone of K2-146: 0.093–0.242 AU (conservative: 0.117–0.230 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on K2-146 b — one full orbit around K2-146 — lasts 2.64 Earth days, shorter than Mercury's 88-day year. Its orbit is mildly elliptical (eccentricity 0.13).
How Was K2-146 b Discovered?
K2-146 b was discovered in 2018 using the transit method, with observations from K2.
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is K2-146 b?
K2-146 b is 258.6 light-years (79.3 parsecs) from Earth. Light arriving here tonight left the planet around the year 1768. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 4,551,360 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. K2-146 b scores 0.30, ranking #1,259 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: K2-146
K2-146
- Surface temperature
- 3,385 K (Sun: 5,772 K)
- Mass
- 0.33 M☉
- Radius
- 0.33 R☉
- Age
- 5.0 billion years (Sun: 4.6)
The K2-146 Planetary System
K2-146 b is one of 2 known planets in the K2-146 system. Its siblings:
- K2-146 c (Super Earth)
K2-146 b — Complete Data
| Radius | 2.050 Earth radii (0.183 Jupiter radii) |
|---|---|
| Mass | 5.77 Earth masses (0.018 Jupiter masses) |
| Density | 3.69 g/cm³ (Earth: 5.51) |
| Orbital period | 2.64 days |
| Eccentricity | 0.129 |
| Earth Similarity Index | 0.30 |
| Distance from Earth | 258.6 light-years (79.3 parsecs) |
| Constellation | Cancer |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2018 |
Data: NASA Exoplanet Archive, last updated 2019-08-09. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-146 b
Is K2-146 b habitable?
K2-146 b is not known to orbit within the habitable zone of K2-146, and as a super-Earth it is an unlikely candidate for life as we know it.
How far away is K2-146 b?
K2-146 b is about 259 light-years from Earth in the constellation Cancer. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 4,551,360 years to get there.
How big is K2-146 b compared to Earth?
K2-146 b has 2.05 times the radius of Earth and about 5.8 times its mass.
How long is a year on K2-146 b?
One orbit around K2-146 takes 2.6 Earth days — short enough that 138 of its years would fit into one Earth year.
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