K2-140 b
K2-140 b is a hot Jupiter orbiting the G6 V star K2-140 in the constellation Virgo. It lies about 1,135 light-years from Earth and was discovered in 2017 using the transit method.
How Big Is K2-140 b?
K2-140 b has a radius of 13.56 times that of Earth, or 1.21 times the radius of Jupiter. Its mass is 296 times that of Earth, giving it a density of 0.66 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is K2-140 b in the Habitable Zone?
K2-140 b orbits inside the inner edge of the habitable zone of K2-140. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of K2-140: 0.752–1.781 AU (conservative: 0.952–1.688 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on K2-140 b
The equilibrium temperature of K2-140 b is about 962 K (689 °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. It receives 204 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on K2-140 b — one full orbit around K2-140 — lasts 6.57 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.068 AU — closer to its star than Mercury is to the Sun.
How Was K2-140 b Discovered?
K2-140 b was discovered in 2017 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 K2-140 b?
K2-140 b is 1,134.8 light-years (347.9 parsecs) from Earth. Light arriving here tonight left the planet about 1,135 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 19,972,480 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. K2-140 b scores 0.07, ranking #4,897 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: K2-140
K2-140
- Spectral type
- G6 V
- Surface temperature
- 5,585 K (Sun: 5,772 K)
- Mass
- 0.96 M☉
- Radius
- 1.06 R☉
- Age
- 9.8 billion years (Sun: 4.6)
Planetary System
K2-140 b is the only planet known to orbit K2-140 so far.
K2-140 b — Complete Data
| Radius | 13.563 Earth radii (1.210 Jupiter radii) |
|---|---|
| Mass | 295.58 Earth masses (0.930 Jupiter masses) |
| Density | 0.66 g/cm³ (Earth: 5.51) |
| Orbital period | 6.57 days |
| Orbital distance | 0.068 AU |
| Equilibrium temperature | 962 K (689 °C) |
| Stellar irradiation | 204.00× Earth |
| Earth Similarity Index | 0.07 |
| Distance from Earth | 1,134.8 light-years (347.9 parsecs) |
| Constellation | Virgo |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2017 |
Data: NASA Exoplanet Archive, last updated 2021-07-12. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-140 b
Is K2-140 b habitable?
No — K2-140 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is K2-140 b?
K2-140 b is about 1,135 light-years from Earth in the constellation Virgo. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 19,972,480 years to get there.
How big is K2-140 b compared to Earth?
K2-140 b has 13.56 times the radius of Earth and about 296 times its mass.
How long is a year on K2-140 b?
One orbit around K2-140 takes 6.6 Earth days — short enough that 56 of its years would fit into one Earth year.
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