K2-290 b
K2-290 b is a super-Earth orbiting K2-290 in the constellation Libra. It lies about 890 light-years from Earth and was discovered in 2019 using the transit method.
How Big Is K2-290 b?
K2-290 b has a radius of 3.06 times that of Earth. Its mass is 10.9 times that of Earth, giving it a density of 4.10 g/cm³ — between that of rocky and gaseous planets.
Is K2-290 b in the Habitable Zone?
K2-290 b orbits inside the inner edge of the habitable zone of K2-290. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of K2-290: 1.307–3.043 AU (conservative: 1.655–2.885 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on K2-290 b
The equilibrium temperature of K2-290 b is about 1,230 K (957 °C) — hot enough to melt many metals. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C.
Orbit and Year Length
A year on K2-290 b — one full orbit around K2-290 — lasts 9.21 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.092 AU — closer to its star than Mercury is to the Sun.
How Was K2-290 b Discovered?
K2-290 b was discovered in 2019 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 K2-290 b?
K2-290 b is 890.1 light-years (272.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1136. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 15,665,760 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. K2-290 b scores 0.21, ranking #3,757 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: K2-290
K2-290 b belongs to a system of 3 stars; it orbits K2-290.
K2-290
- Surface temperature
- 6,302 K (Sun: 5,772 K)
- Mass
- 1.19 M☉
- Radius
- 1.51 R☉
- Age
- 4.0 billion years (Sun: 4.6)
The K2-290 Planetary System
K2-290 b is one of 2 known planets in the K2-290 system. Its siblings:
- K2-290 c (Cold Gas Giant)
K2-290 b — Complete Data
| Radius | 3.060 Earth radii (0.273 Jupiter radii) |
|---|---|
| Mass | 10.90 Earth masses (0.034 Jupiter masses) |
| Density | 4.10 g/cm³ (Earth: 5.51) |
| Orbital period | 9.21 days |
| Orbital distance | 0.092 AU |
| Equilibrium temperature | 1,230 K (957 °C) |
| Earth Similarity Index | 0.21 |
| Distance from Earth | 890.1 light-years (272.9 parsecs) |
| Constellation | Libra |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2019 |
Data: NASA Exoplanet Archive, last updated 2019-01-22. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-290 b
Is K2-290 b habitable?
No — K2-290 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is K2-290 b?
K2-290 b is about 890 light-years from Earth in the constellation Libra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 15,665,760 years to get there.
How big is K2-290 b compared to Earth?
K2-290 b has 3.06 times the radius of Earth and about 10.9 times its mass.
How long is a year on K2-290 b?
One orbit around K2-290 takes 9.2 Earth days — short enough that 40 of its years would fit into one Earth year.
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