Kepler-427 b
Kepler-427 b is a hot Jupiter orbiting the G2 V star Kepler-427 in the constellation Lyra. It lies about 3,320 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is Kepler-427 b?
Kepler-427 b has a radius of 13.79 times that of Earth, or 1.23 times the radius of Jupiter. Its mass is 92.2 times that of Earth, giving it a density of 0.16 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is Kepler-427 b in the Habitable Zone?
Kepler-427 b orbits inside the inner edge of the habitable zone of Kepler-427. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-427: 1.047–2.464 AU (conservative: 1.326–2.336 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on Kepler-427 b
The equilibrium temperature of Kepler-427 b is about 1,100 K (827 °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.
Orbit and Year Length
A year on Kepler-427 b — one full orbit around Kepler-427 — lasts 10.3 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.091 AU — closer to its star than Mercury is to the Sun. Its orbit is highly elliptical (eccentricity 0.57), swinging dramatically closer to and farther from its star.
How Was Kepler-427 b Discovered?
Kepler-427 b 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-427 b?
Kepler-427 b is 3,319.6 light-years (1,017.8 parsecs) from Earth. Light arriving here tonight left the planet about 3,320 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 58,424,960 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-427 b scores 0.07, ranking #4,965 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-427
Kepler-427
- Spectral type
- G2 V
- Surface temperature
- 5,800 K (Sun: 5,772 K)
- Mass
- 0.96 M☉
- Radius
- 1.35 R☉
- Luminosity
- 1.9498 L☉
- Age
- 7.0 billion years (Sun: 4.6)
Planetary System
Kepler-427 b is the only planet known to orbit Kepler-427 so far.
Kepler-427 b — Complete Data
| Radius | 13.790 Earth radii (1.230 Jupiter radii) |
|---|---|
| Mass | 92.17 Earth masses (0.290 Jupiter masses) |
| Density | 0.16 g/cm³ (Earth: 5.51) |
| Orbital period | 10.29 days |
| Orbital distance | 0.091 AU |
| Eccentricity | 0.570 |
| Equilibrium temperature | 1,100 K (827 °C) |
| Earth Similarity Index | 0.07 |
| Distance from Earth | 3,319.6 light-years (1,017.8 parsecs) |
| Constellation | Lyra |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2014-10-03. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-427 b
Is Kepler-427 b habitable?
No — Kepler-427 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-427 b?
Kepler-427 b is about 3,320 light-years from Earth in the constellation Lyra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 58,424,960 years to get there.
How big is Kepler-427 b compared to Earth?
Kepler-427 b has 13.79 times the radius of Earth and about 92.2 times its mass.
How long is a year on Kepler-427 b?
One orbit around Kepler-427 takes 10.3 Earth days — short enough that 35 of its years would fit into one Earth year.
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