Kepler-725 b
Kepler-725 b is a cold gas giant orbiting Kepler-725 in the constellation Lyra. It lies about 2,474 light-years from Earth and was discovered in 2016 using the transit method.
How Big Is Kepler-725 b?
Kepler-725 b has a radius of 10.80 times that of Earth, or 0.96 times the radius of Jupiter.
Is Kepler-725 b in the Habitable Zone?
Kepler-725 b orbits inside the inner edge of the habitable zone of Kepler-725. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-725: 0.589–1.403 AU (conservative: 0.746–1.330 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 Kepler-725 b
The equilibrium temperature of Kepler-725 b is about 514 K (241 °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. It receives 12.10 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on Kepler-725 b — one full orbit around Kepler-725 — lasts 39.6 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.224 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.23).
How Was Kepler-725 b Discovered?
Kepler-725 b was discovered in 2016 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-725 b?
Kepler-725 b is 2,473.8 light-years (758.5 parsecs) from Earth. Light arriving here tonight left the planet about 2,474 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 43,538,880 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-725 b scores 0.17, ranking #4,082 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-725
Kepler-725
- Surface temperature
- 5,395 K (Sun: 5,772 K)
- Mass
- 0.95 M☉
- Radius
- 0.88 R☉
- Age
- 1.6 billion years (Sun: 4.6)
The Kepler-725 Planetary System
Kepler-725 b is one of 2 known planets in the Kepler-725 system. Its siblings:
- Kepler-725 c (Super Earth)
Kepler-725 b — Complete Data
| Radius | 10.800 Earth radii (0.964 Jupiter radii) |
|---|---|
| Orbital period | 39.64 days |
| Orbital distance | 0.224 AU |
| Eccentricity | 0.231 |
| Equilibrium temperature | 514 K (241 °C) |
| Stellar irradiation | 12.10× Earth |
| Earth Similarity Index | 0.17 |
| Distance from Earth | 2,473.8 light-years (758.5 parsecs) |
| Constellation | Lyra |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2016 |
Data: NASA Exoplanet Archive, last updated 2025-06-26. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-725 b
Is Kepler-725 b habitable?
No — Kepler-725 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-725 b?
Kepler-725 b is about 2,474 light-years from Earth in the constellation Lyra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 43,538,880 years to get there.
How big is Kepler-725 b compared to Earth?
Kepler-725 b has 10.80 times the radius of Earth.
How long is a year on Kepler-725 b?
One orbit around Kepler-725 takes 39.6 Earth days.
Explore Kepler-725 b in the app
Browse, filter and compare 6,000+ exoplanets on iPhone, iPad and Apple Watch — with habitable-zone views, widgets and offline data.
