Kepler-409 b
Kepler-409 b is a terrestrial planet orbiting Kepler-409 in the constellation Cygnus. It lies about 222 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is Kepler-409 b?
Kepler-409 b has a radius of 1.20 times that of Earth. Its mass is 6.0 times that of Earth, giving it a density of 19.00 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is Kepler-409 b in the Habitable Zone?
Kepler-409 b orbits inside the inner edge of the habitable zone of Kepler-409. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-409: 0.605–1.441 AU (conservative: 0.766–1.366 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on Kepler-409 b
The equilibrium temperature of Kepler-409 b is about 438 K (165 °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 6.15 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on Kepler-409 b — one full orbit around Kepler-409 — lasts 69.0 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.319 AU — closer to its star than Mercury is to the Sun. Its orbit is highly elliptical (eccentricity 0.69), swinging dramatically closer to and farther from its star.
How Was Kepler-409 b Discovered?
Kepler-409 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-409 b?
Kepler-409 b is 222.4 light-years (68.2 parsecs) from Earth. Light arriving here tonight left the planet around the year 1804. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 3,914,240 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-409 b scores 0.44, ranking #367 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-409
Kepler-409
- Surface temperature
- 5,421 K (Sun: 5,772 K)
- Mass
- 0.91 M☉
- Radius
- 0.90 R☉
- Age
- 5.8 billion years (Sun: 4.6)
Planetary System
Kepler-409 b is the only planet known to orbit Kepler-409 so far.
Kepler-409 b — Complete Data
| Radius | 1.199 Earth radii (0.107 Jupiter radii) |
|---|---|
| Mass | 6.00 Earth masses (0.019 Jupiter masses) |
| Density | 19.00 g/cm³ (Earth: 5.51) |
| Orbital period | 68.96 days |
| Orbital distance | 0.319 AU |
| Eccentricity | 0.690 |
| Equilibrium temperature | 438 K (165 °C) |
| Stellar irradiation | 6.15× Earth |
| Earth Similarity Index | 0.44 |
| Distance from Earth | 222.4 light-years (68.2 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2023-04-17. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-409 b
Is Kepler-409 b habitable?
No — Kepler-409 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-409 b?
Kepler-409 b is about 222 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 3,914,240 years to get there.
How big is Kepler-409 b compared to Earth?
Kepler-409 b has 1.20 times the radius of Earth and about 6.0 times its mass.
How long is a year on Kepler-409 b?
One orbit around Kepler-409 takes 69.0 Earth days.
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