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Exoplanet Kepler 21 A b
Exoplanet Kepler 21 A b orbits star Kepler 21 A that lies 354 light years away from the Sun.
It weighs about 6.68 Earth masses and orbits its star much closer than Earth orbits Sun.
Sun distance
354 light years
354 light years
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Kepler 21 A b
Exoplanet, super-earth
Star: Kepler 21 A
Distance from the star: 0.0434281 AU
Orbit around star: 2.785821 days
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Orbital period
Orbital period of exoplanet Kepler 21 A b around its star is 2.785821 days.
The orbital period of an exoplanet is the time it takes to complete one full orbit around its star, usually measured in days. Most of the exoplanets discovered so far have orbital periods of less than one year...
More about Orbital period in StellarGuide
Eccentricity: 0.02Basic characteristic
Mass: 6.68 M Earth
Exoplanet mass
Exoplanet Kepler 21 A b has 6.68 Earth masses, or 0.46 times the mass of Uranus.
The mass of an exoplanet is one of the most important characteristics for understanding what kind of world it is — whether it’s small and rocky like Earth or large and gaseous like Jupiter. Mass provides key information about the planet’s composition, gravity, and formation history...
More about Exoplanet mass in StellarGuide
Size: 1.639 R Earth | 0.1 R Jupiter
Density: 8365 kg/m3 | 151.73 % Earth
Temperature: 2015 K | 1741.85 °C
Year of discovery: 2012 (transit)
Other designations of this exoplanet
HIP 94112 b, Kepler-21 b, KOI-975 b, KIC 3632418 b, TYC 3120-963-1 b, 2MASS J19092683+3842505 b, HD 179070 b
HIP 94112 b, Kepler-21 b, KOI-975 b, KIC 3632418 b, TYC 3120-963-1 b, 2MASS J19092683+3842505 b, HD 179070 b
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Kepler 21 system structure
Exoplanet Kepler 21 A b orbits star Kepler 21 A, which has bigger mass than Sun. It is one of 2 known exoplanets orbiting this star.
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Kepler 21 A | ||||||||
| Kepler 21 A b | 0.04 AU | 6.7 M⊕ | 1.6 R⊕ | 2.8 days | |||||
| Kepler 21 A c unconfirmed |
17.7 AU | 1176.3 M⊕ | 25567 days | ||||||
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Kepler 21 B | 87 AU | |||||||
Comparison
When comparing to the Solar system planets, Kepler 21 A b has 46 % of mass of Uranus and it orbits its star closer than Mercury orbits the Sun.
| Mercury | Venus | Earth | Mars | Jupiter | Saturn | Uranus | Neptune | ||
|---|---|---|---|---|---|---|---|---|---|
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Mass | 121.45 | 8.2 | 6.68 | 60.73 | 0.02 | 0.07 | 0.46 | 0.39 |
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Size | 4.28 | 1.73 | 1.64 | 3.09 | 0.15 | 0.18 | 0.41 | 0.43 |
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Density | 1.55 | 1.6 | 1.52 | 2.05 | 6.72 | 12.01 | 6.65 | 4.84 |
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Distance | 0.11 | 0.06 | 0.04 | 0.03 | 0.01 | 0 | 0 | 0 |
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Temperature | 4.58 | 2.73 | 7 | 9.69 | 12.36 | 15.15 | 25.83 | 27.99 |
Habitability
Habitable zone of the star: 2 - 2.9 AU
The planet orbits too close to its star and is exposed to extreme temperatures and radiation prohibiting life as we know it.