Kepler-434 b
Kepler-434 b is a cold gas giant orbiting Kepler-434 in the constellation Cygnus. It lies about 3,987 light-years from Earth and was discovered in 2015 using the transit method.
How Big Is Kepler-434 b?
Kepler-434 b has a radius of 12.67 times that of Earth, or 1.13 times the radius of Jupiter. Its mass is 909 times that of Earth, giving it a density of 2.40 g/cm³ — between that of rocky and gaseous planets.
Is Kepler-434 b in the Habitable Zone?
Kepler-434 b orbits inside the inner edge of the habitable zone of Kepler-434. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-434: 1.084–2.542 AU (conservative: 1.373–2.410 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on Kepler-434 b
The equilibrium temperature of Kepler-434 b is about 1,000 K (727 °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-434 b — one full orbit around Kepler-434 — lasts 12.9 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.114 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.13).
How Was Kepler-434 b Discovered?
Kepler-434 b was discovered in 2015 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-434 b?
Kepler-434 b is 3,987.4 light-years (1,222.5 parsecs) from Earth. Light arriving here tonight left the planet about 3,987 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 70,178,240 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-434 b scores 0.08, ranking #4,747 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-434
Kepler-434
- Surface temperature
- 5,977 K (Sun: 5,772 K)
- Mass
- 1.20 M☉
- Radius
- 1.38 R☉
- Luminosity
- 2.1380 L☉
- Age
- 4.0 billion years (Sun: 4.6)
Planetary System
Kepler-434 b is the only planet known to orbit Kepler-434 so far.
Kepler-434 b — Complete Data
| Radius | 12.670 Earth radii (1.130 Jupiter radii) |
|---|---|
| Mass | 908.96 Earth masses (2.860 Jupiter masses) |
| Density | 2.40 g/cm³ (Earth: 5.51) |
| Orbital period | 12.87 days |
| Orbital distance | 0.114 AU |
| Eccentricity | 0.131 |
| Equilibrium temperature | 1,000 K (727 °C) |
| Earth Similarity Index | 0.08 |
| Distance from Earth | 3,987.4 light-years (1,222.5 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2015 |
Data: NASA Exoplanet Archive, last updated 2015-01-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-434 b
Is Kepler-434 b habitable?
No — Kepler-434 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-434 b?
Kepler-434 b is about 3,987 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 70,178,240 years to get there.
How big is Kepler-434 b compared to Earth?
Kepler-434 b has 12.67 times the radius of Earth and about 909 times its mass.
How long is a year on Kepler-434 b?
One orbit around Kepler-434 takes 12.9 Earth days — short enough that 28 of its years would fit into one Earth year.
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