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Entering orbit…
Habitability
7/ 100
Uninhabitable

K2-199 b

Rocky TerrestrialUninhabitable352 light years awayFound 2018

K2-199 b, from the NASA Exoplanet Archive (found 2018). Measured: 6.9 Earth masses, 0.0382 AU, a 4491 K K-type star. Composition inferred from a measured bulk density of 1.33x Earth's, which is rock and iron, with a day locked to its 3.2-day year, as anything orbiting this close would be.

Host star

K2-199

Type
K-type (Orange)
Temperature
4,491 K
Radius
0.682 ☉
Mass
0.711 ☉
Known planets
2, including this one
Luminosity
0.185 ☉

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

Magnetic FieldExtreme Activity
Why is this a Rocky Terrestrial?Your planet is dominated by silicate (25.0%) and iron (12.5%) 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: 25.0% + Iron: 12.5% + Magnesium: 3.8%✓ Mass: 6.9x 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
7
Contributing Factors
temperature5
Scorching - hot enough to melt lead, though rock stays solid; no chance for life
atmosphere70
Nitrogen atmosphere provides protection but not breathable
water8
Limited water content - boiling away, little would be retained
magnetic Field100
Magnetic field provides radiation protection
geology40
Extreme volcanic activity may be hazardous
Organic Chemistry80
Core organic elements (CHNO) present
rotation65
Slow rotation - significant day/night temperature variations, but life can adapt

Physical Properties

Mass
6.90x Earth (4.12e+25 kg)
Radius
1.90x Earth (12,129 km)
This planet: 1.90× Earth radiusEarth: 1× (baseline)
Surface Gravity
1.90x Earth (18.7 m/s²)
Surface Temperature
946 K (673 °C / 1,244 °F)
Rotation Period
77.5 hours/day (slower than Earth)
This planet: 78 h/dayEarth: 24 h/day

Orbital Environment

Star Type
K-type (Orange)
Distance from Star
0.04 AU (5.71 million km)
Orbital Period
3 days
Time Dilation
Clocks run 8.6 seconds per year slower than deep space — about 11 minutes over a lifetime

Atmosphere

Thin CO₂ and nitrogen atmosphere

Elemental Composition

O - Oxygen
31.3%
Si - Silicon
25.0%
Fe - Iron
12.5%

Surface Characteristics

Rocky surface with impact craters, possible volcanic features
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