Kepler-99 b
Kepler-99 b is a super-Earth orbiting Kepler-99 in the constellation Cygnus. It lies about 680 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is Kepler-99 b?
Kepler-99 b has a radius of 1.48 times that of Earth. Its mass is 6.2 times that of Earth, giving it a density of 10.90 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is Kepler-99 b in the Habitable Zone?
The position of Kepler-99 b relative to the habitable zone of Kepler-99 cannot be precisely determined from the available orbital data.
Habitable zone of Kepler-99: 0.396–0.965 AU (conservative: 0.501–0.915 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-99 b — one full orbit around Kepler-99 — lasts 4.60 Earth days, shorter than Mercury's 88-day year.
How Was Kepler-99 b Discovered?
Kepler-99 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-99 b?
Kepler-99 b is 679.6 light-years (208.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1347. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 11,960,960 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-99 b scores 0.29, ranking #1,651 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-99
Kepler-99 b belongs to a system of 2 stars; it orbits Kepler-99.
Kepler-99
- Surface temperature
- 4,782 K (Sun: 5,772 K)
- Mass
- 0.79 M☉
- Radius
- 0.73 R☉
- Age
- 1.5 billion years (Sun: 4.6)
Planetary System
Kepler-99 b is the only planet known to orbit Kepler-99 so far.
Kepler-99 b — Complete Data
| Radius | 1.480 Earth radii (0.132 Jupiter radii) |
|---|---|
| Mass | 6.15 Earth masses (0.019 Jupiter masses) |
| Density | 10.90 g/cm³ (Earth: 5.51) |
| Orbital period | 4.60 days |
| Earth Similarity Index | 0.29 |
| Distance from Earth | 679.6 light-years (208.4 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2014-05-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-99 b
Is Kepler-99 b habitable?
Kepler-99 b is not known to orbit within the habitable zone of Kepler-99, and as a super-Earth it is an unlikely candidate for life as we know it.
How far away is Kepler-99 b?
Kepler-99 b is about 680 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 11,960,960 years to get there.
How big is Kepler-99 b compared to Earth?
Kepler-99 b has 1.48 times the radius of Earth and about 6.2 times its mass.
How long is a year on Kepler-99 b?
One orbit around Kepler-99 takes 4.6 Earth days — short enough that 79 of its years would fit into one Earth year.
Explore Kepler-99 b in the app
Browse, filter and compare 6,000+ exoplanets on iPhone, iPad and Apple Watch — with habitable-zone views, widgets and offline data.
