K2-37 d
K2-37 d is a super-Earth orbiting K2-37 in the constellation Scorpius. It lies about 587 light-years from Earth and was discovered in 2016 using the transit method.
How Big Is K2-37 d?
K2-37 d has a radius of 2.31 times that of Earth. Its mass is 12.5 times that of Earth, giving it a density of 4.70 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is K2-37 d in the Habitable Zone?
The position of K2-37 d relative to the habitable zone of K2-37 cannot be precisely determined from the available orbital data.
Habitable zone of K2-37: 0.534–1.274 AU (conservative: 0.676–1.208 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 ›
Temperature on K2-37 d
The equilibrium temperature of K2-37 d is about 646 K (373 °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 41.30 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on K2-37 d — one full orbit around K2-37 — lasts 14.1 Earth days, shorter than Mercury's 88-day year.
How Was K2-37 d Discovered?
K2-37 d was discovered in 2016 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 K2-37 d?
K2-37 d is 586.9 light-years (179.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1440. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 10,329,440 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. K2-37 d scores 0.26, ranking #2,741 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: K2-37
K2-37
- Surface temperature
- 5,352 K (Sun: 5,772 K)
- Mass
- 0.84 M☉
- Radius
- 0.81 R☉
The K2-37 Planetary System
K2-37 d is one of 3 known planets in the K2-37 system. Its siblings:
K2-37 d — Complete Data
| Radius | 2.310 Earth radii (0.206 Jupiter radii) |
|---|---|
| Mass | 12.50 Earth masses (0.039 Jupiter masses) |
| Density | 4.70 g/cm³ (Earth: 5.51) |
| Orbital period | 14.09 days |
| Equilibrium temperature | 646 K (373 °C) |
| Stellar irradiation | 41.30× Earth |
| Earth Similarity Index | 0.26 |
| Distance from Earth | 586.9 light-years (179.9 parsecs) |
| Constellation | Scorpius |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2016 |
Data: NASA Exoplanet Archive, last updated 2025-09-17. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-37 d
Is K2-37 d habitable?
K2-37 d is not known to orbit within the habitable zone of K2-37, and as a super-Earth it is an unlikely candidate for life as we know it.
How far away is K2-37 d?
K2-37 d is about 587 light-years from Earth in the constellation Scorpius. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 10,329,440 years to get there.
How big is K2-37 d compared to Earth?
K2-37 d has 2.31 times the radius of Earth and about 12.5 times its mass.
How long is a year on K2-37 d?
One orbit around K2-37 takes 14.1 Earth days — short enough that 26 of its years would fit into one Earth year.
Explore K2-37 d in the app
Browse, filter and compare 6,000+ exoplanets on iPhone, iPad and Apple Watch — with habitable-zone views, widgets and offline data.
