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Entering orbit…
Habitability
0/ 100
Uninhabitable

Kepler-99 b

Rocky TerrestrialUninhabitable678 light years awayFound 2014

Kepler-99 b, from the NASA Exoplanet Archive (found 2014). Measured: 6.15 Earth masses, 0.0507 AU, a 4782 K K-type star. Composition inferred from a measured bulk density of 1.90x Earth's, far too high for silicates alone — an iron-rich world, with a day locked to its 4.6-day year, as anything orbiting this close would be.

Host star

Kepler-99

Type
K-type (Orange)
Temperature
4,782 K
Radius
0.73 ☉
Mass
0.79 ☉
Known planets
1 (this one)
Luminosity
0.260 ☉

Published by the NASA Exoplanet Archive. This world’s temperature and habitability score are computed from this star’s measured luminosity, not from a stand-in for its class.

Rocky Terrestrial

Extreme Activity
Why is this a Rocky Terrestrial?Your planet is dominated by silicate (36.6%) and iron (24.4%) content, forming a rocky terrestrial body.
Rocky terrestrial planets are primarily composed of silicate rocks and metals. They're the most common type of small planet in the universe.
Classification Criteria:
✓ Silicon: 36.6% + Iron: 24.4% + Magnesium: 12.2%✓ Mass: 6.2x Earth (terrestrial range)
Further reading
The Little Book of ExoplanetsJoshua WinnHow these worlds are found, and what a measurement can honestly tell us.Exoplanets: Diamond Worlds, Super Earths, Pulsar PlanetsMichael Summers & James TrefilThe strange end of the catalogue — carbon worlds, molten rock, planets orbiting dead stars.Envisioning ExoplanetsMichael CarrollWhat these worlds might look like from the ground, painted from the same measurements this page renders.Imagined LifeJames Trefil & Michael SummersWhat could live on a world like this one: ice shells, supergravity, tidally locked twilight.
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Habitability ScoreUninhabitable
0
Contributing Factors
temperature5
Scorching - hot enough to melt lead, though rock stays solid; no chance for life
atmosphere10
No atmosphere - exposed to radiation and temperature extremes
water0
No water - the recipe has no hydrogen and oxygen to form it
magnetic Field30
No magnetic field - vulnerable to solar radiation
geology40
Extreme volcanic activity may be hazardous
Organic Chemistry20
Limited organic chemistry potential
rotation30
Very slow rotation - extreme temperature swings between eternal day and night sides

Physical Properties

Mass
6.15x Earth (3.67e+25 kg)
Radius
1.83x Earth (11,673 km)
This planet: 1.83× Earth radiusEarth: 1× (baseline)
Surface Gravity
1.83x Earth (18.0 m/s²)
Surface Temperature
882 K (608 °C / 1,127 °F)
Rotation Period
110.4 hours/day (slower than Earth)
This planet: 110 h/dayEarth: 24 h/day

Orbital Environment

Star Type
K-type (Orange)
Distance from Star
0.05 AU (7.58 million km)
Orbital Period
5 days
Time Dilation
Clocks run 6.5 seconds per year slower than deep space — about 9 minutes over a lifetime

Atmosphere

Minimal or none

Elemental Composition

Si - Silicon
36.6%
Fe - Iron
24.4%
Mg - Magnesium
12.2%

Surface Characteristics

Rocky surface with impact craters, possible volcanic features
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