Kepler-102 f
Kepler-102 f is a terrestrial planet orbiting Kepler-102 in the constellation Lyra. It lies about 352 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is Kepler-102 f?
Kepler-102 f has a radius of 0.86 times that of Earth. Its mass is 4.3 times that of Earth, giving it a density of 37.00 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is Kepler-102 f in the Habitable Zone?
Kepler-102 f orbits inside the inner edge of the habitable zone of Kepler-102. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-102: 0.411–0.998 AU (conservative: 0.521–0.946 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on Kepler-102 f
The equilibrium temperature of Kepler-102 f is about 495 K (222 °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 10.00 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on Kepler-102 f — one full orbit around Kepler-102 — lasts 27.5 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.166 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.10).
How Was Kepler-102 f Discovered?
Kepler-102 f 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-102 f?
Kepler-102 f is 351.6 light-years (107.8 parsecs) from Earth. Light arriving here tonight left the planet around the year 1675. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 6,188,160 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-102 f scores 0.42, ranking #403 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-102
Kepler-102
- Surface temperature
- 4,909 K (Sun: 5,772 K)
- Mass
- 0.80 M☉
- Radius
- 0.72 R☉
- Age
- 1.1 billion years (Sun: 4.6)
The Kepler-102 Planetary System
Kepler-102 f is one of 5 known planets in the Kepler-102 system. Its siblings:
- Kepler-102 b (Terrestrial)
- Kepler-102 c (Terrestrial)
- Kepler-102 d (Terrestrial)
- Kepler-102 e (Mini Neptune)
Kepler-102 f — Complete Data
| Radius | 0.861 Earth radii (0.077 Jupiter radii) |
|---|---|
| Mass | 4.30 Earth masses (0.014 Jupiter masses) |
| Density | 37.00 g/cm³ (Earth: 5.51) |
| Orbital period | 27.45 days |
| Orbital distance | 0.166 AU |
| Eccentricity | 0.100 |
| Equilibrium temperature | 495 K (222 °C) |
| Stellar irradiation | 10.00× Earth |
| Earth Similarity Index | 0.42 |
| Distance from Earth | 351.6 light-years (107.8 parsecs) |
| Constellation | Lyra |
| 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-102 f
Is Kepler-102 f habitable?
No — Kepler-102 f orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-102 f?
Kepler-102 f is about 352 light-years from Earth in the constellation Lyra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 6,188,160 years to get there.
How big is Kepler-102 f compared to Earth?
Kepler-102 f has 0.86 times the radius of Earth and about 4.3 times its mass.
How long is a year on Kepler-102 f?
One orbit around Kepler-102 takes 27.5 Earth days — short enough that 13 of its years would fit into one Earth year.
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