Kepler-444 b
Kepler-444 b is a terrestrial planet orbiting the K star Kepler-444 in the constellation Lyra. It lies about 119 light-years from Earth and was discovered in 2015 using the transit method.
How Big Is Kepler-444 b?
Kepler-444 b has a radius of 0.40 times that of Earth.
Is Kepler-444 b in the Habitable Zone?
Kepler-444 b orbits inside the inner edge of the habitable zone of Kepler-444. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-444: 0.448–1.082 AU (conservative: 0.568–1.026 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 ›
Orbit and Year Length
A year on Kepler-444 b — one full orbit around Kepler-444 — lasts 3.60 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.042 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.16).
How Was Kepler-444 b Discovered?
Kepler-444 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-444 b?
Kepler-444 b is 118.8 light-years (36.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1908. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,090,880 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-444 b scores 0.24, ranking #3,372 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-444
Kepler-444 b belongs to a system of 3 stars; it orbits Kepler-444.
Kepler-444
- Spectral type
- K
- Surface temperature
- 5,046 K (Sun: 5,772 K)
- Mass
- 0.76 M☉
- Radius
- 0.75 R☉
- Age
- 11.2 billion years (Sun: 4.6)
The Kepler-444 Planetary System
Kepler-444 b is one of 5 known planets in the Kepler-444 system. Its siblings:
- Kepler-444 c (Terrestrial)
- Kepler-444 d (Terrestrial)
- Kepler-444 e (Terrestrial)
- Kepler-444 f (Terrestrial)
Kepler-444 b — Complete Data
| Radius | 0.403 Earth radii (0.036 Jupiter radii) |
|---|---|
| Orbital period | 3.60 days |
| Orbital distance | 0.042 AU |
| Eccentricity | 0.160 |
| Earth Similarity Index | 0.24 |
| Distance from Earth | 118.8 light-years (36.4 parsecs) |
| Constellation | Lyra |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2015 |
Data: NASA Exoplanet Archive, last updated 2015-01-29. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-444 b
Is Kepler-444 b habitable?
No — Kepler-444 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-444 b?
Kepler-444 b is about 119 light-years from Earth in the constellation Lyra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,090,880 years to get there.
How big is Kepler-444 b compared to Earth?
Kepler-444 b has 0.40 times the radius of Earth.
How long is a year on Kepler-444 b?
One orbit around Kepler-444 takes 3.6 Earth days — short enough that 101 of its years would fit into one Earth year.
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