Kepler-126 d
Kepler-126 d is a mini-Neptune orbiting Kepler-126 in the constellation Cygnus. It lies about 774 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is Kepler-126 d?
Kepler-126 d has a radius of 2.50 times that of Earth.
Is Kepler-126 d in the Habitable Zone?
Kepler-126 d orbits inside the inner edge of the habitable zone of Kepler-126. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-126: 1.155–2.694 AU (conservative: 1.463–2.554 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 Kepler-126 d — one full orbit around Kepler-126 — lasts 100.3 Earth days, between the years of Mercury (88 days) and Earth (365 days). It orbits at an average distance of 0.448 AU — comparable to the inner Solar System.
How Was Kepler-126 d Discovered?
Kepler-126 d was discovered in 2014 using the transit method, with observations from Kepler.
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 Kepler-126 d?
Kepler-126 d is 774.3 light-years (237.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1252. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 13,627,680 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-126 d scores 0.32, ranking #1,077 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-126
Kepler-126
- Surface temperature
- 6,239 K (Sun: 5,772 K)
- Radius
- 1.36 R☉
The Kepler-126 Planetary System
Kepler-126 d is one of 3 known planets in the Kepler-126 system. Its siblings:
- Kepler-126 b (Super Earth)
- Kepler-126 c (Super Earth)
Kepler-126 d — Complete Data
| Radius | 2.500 Earth radii (0.223 Jupiter radii) |
|---|---|
| Orbital period | 100.28 days |
| Orbital distance | 0.448 AU |
| Earth Similarity Index | 0.32 |
| Distance from Earth | 774.3 light-years (237.4 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2014-05-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-126 d
Is Kepler-126 d habitable?
No — Kepler-126 d orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-126 d?
Kepler-126 d is about 774 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 13,627,680 years to get there.
How big is Kepler-126 d compared to Earth?
Kepler-126 d has 2.50 times the radius of Earth.
How long is a year on Kepler-126 d?
One orbit around Kepler-126 takes 100.3 Earth days.
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