Kepler-10 d
Kepler-10 d is a Neptune-like planet orbiting Kepler-10 in the constellation Draco. It lies about 605 light-years from Earth and was discovered in 2023 using the radial velocity method.
Is Kepler-10 d in the Habitable Zone?
Kepler-10 d orbits inside the inner edge of the habitable zone of Kepler-10. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-10: 0.783–1.849 AU (conservative: 0.992–1.753 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on Kepler-10 d
The equilibrium temperature of Kepler-10 d is about 387 K (114 °C) — hotter than anywhere on Earth. 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 Kepler-10 d — one full orbit around Kepler-10 — lasts 151.1 Earth days, between the years of Mercury (88 days) and Earth (365 days). It orbits at an average distance of 0.538 AU — comparable to the inner Solar System. Its orbit is mildly elliptical (eccentricity 0.19).
How Was Kepler-10 d Discovered?
Kepler-10 d was discovered in 2023 using the radial velocity method, with observations from Roque de los Muchachos Observatory.
The radial velocity method measures the subtle wobble of a star caused by the gravitational pull of an orbiting planet, visible as periodic shifts in the star's light spectrum. The size of the wobble reveals the planet's minimum mass.
How Far Away Is Kepler-10 d?
Kepler-10 d is 605.0 light-years (185.5 parsecs) from Earth. Light arriving here tonight left the planet around the year 1421. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 10,648,000 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. Kepler-10 d scores 0.41, ranking #423 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-10
Kepler-10
- Surface temperature
- 5,708 K (Sun: 5,772 K)
- Mass
- 0.91 M☉
- Radius
- 1.07 R☉
- Age
- 10.6 billion years (Sun: 4.6)
The Kepler-10 Planetary System
Kepler-10 d is one of 3 known planets in the Kepler-10 system. Its siblings:
- Kepler-10 b (Lava World)
- Kepler-10 c (Super Earth)
Kepler-10 d — Complete Data
| Mass (best estimate) | 12.00 Earth masses |
|---|---|
| Orbital period | 151.06 days |
| Orbital distance | 0.538 AU |
| Eccentricity | 0.190 |
| Equilibrium temperature | 387 K (114 °C) |
| Earth Similarity Index | 0.41 |
| Distance from Earth | 605.0 light-years (185.5 parsecs) |
| Constellation | Draco |
| Discovery method | Radial Velocity |
| Discovery facility | Roque de los Muchachos Observatory |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2025-06-11. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-10 d
Is Kepler-10 d habitable?
No — Kepler-10 d orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-10 d?
Kepler-10 d is about 605 light-years from Earth in the constellation Draco. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 10,648,000 years to get there.
How long is a year on Kepler-10 d?
One orbit around Kepler-10 takes 151.1 Earth days.
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