Kepler-433 b
Kepler-433 b is a hot Jupiter orbiting Kepler-433 in the constellation Cygnus. It lies about 6,126 light-years from Earth and was discovered in 2015 using the transit method.
How Big Is Kepler-433 b?
Kepler-433 b has a radius of 16.25 times that of Earth, or 1.45 times the radius of Jupiter. Its mass is 896 times that of Earth, giving it a density of 1.13 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is Kepler-433 b in the Habitable Zone?
Kepler-433 b orbits inside the inner edge of the habitable zone of Kepler-433. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-433: 1.995–4.642 AU (conservative: 2.527–4.401 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on Kepler-433 b
The equilibrium temperature of Kepler-433 b is about 1,776 K (1,503 °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-433 b — one full orbit around Kepler-433 — lasts 5.33 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.068 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.12).
How Was Kepler-433 b Discovered?
Kepler-433 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-433 b?
Kepler-433 b is 6,126.2 light-years (1,878.3 parsecs) from Earth. Light arriving here tonight left the planet about 6,126 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 107,821,120 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-433 b scores 0.06, ranking #5,206 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-433
Kepler-433
- Surface temperature
- 6,360 K (Sun: 5,772 K)
- Mass
- 1.46 M☉
- Radius
- 2.26 R☉
- Luminosity
- 7.5858 L☉
- Age
- 2.7 billion years (Sun: 4.6)
Planetary System
Kepler-433 b is the only planet known to orbit Kepler-433 so far.
Kepler-433 b — Complete Data
| Radius | 16.250 Earth radii (1.450 Jupiter radii) |
|---|---|
| Mass | 896.24 Earth masses (2.820 Jupiter masses) |
| Density | 1.13 g/cm³ (Earth: 5.51) |
| Orbital period | 5.33 days |
| Orbital distance | 0.068 AU |
| Eccentricity | 0.119 |
| Equilibrium temperature | 1,776 K (1,503 °C) |
| Earth Similarity Index | 0.06 |
| Distance from Earth | 6,126.2 light-years (1,878.3 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-433 b
Is Kepler-433 b habitable?
No — Kepler-433 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-433 b?
Kepler-433 b is about 6,126 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 107,821,120 years to get there.
How big is Kepler-433 b compared to Earth?
Kepler-433 b has 16.25 times the radius of Earth and about 896 times its mass.
How long is a year on Kepler-433 b?
One orbit around Kepler-433 takes 5.3 Earth days — short enough that 68 of its years would fit into one Earth year.
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