Host star — K2-332
- Spectral type
- —
- Temperature
- 3,315 K
- Radius
- 0.28 R☉
- Mass
- 0.27 M☉
- Luminosity
- 0.009 L☉
- Distance
- 123.2 pc (402 ly)
Very cool — a faint red dwarf.
K2-332 b
Orbits K2-332 · 402 light-years from Earth
Super-EarthTransit2021ESI 82 · Very Earth-like
Radius
2.20×
Earth
Mass
5.5×
Earth
Year
18d
Temp
266 K
-7°C
Gravity
1.1×
Earth
Distance
402
ly
Could life exist here?
AI analysisK2-332 b is a super-Earth roughly 2.2 times wider than Earth and about 5.5 times as massive, orbiting a small, cool red dwarf star every 17.7 days at a distance of 402 light-years. With an equilibrium temperature of 266 Kelvin (roughly minus 7 degrees Celsius), the planet sits in a temperate zone where liquid water could plausibly exist on its surface, assuming an atmosphere thick enough to retain warmth. Its density of 2.83 grams per cubic centimeter suggests a rocky composition, though we cannot yet directly confirm atmospheric composition or surface conditions. The substantial habitability score of 82 out of 100 reflects these promising conditions, but significant uncertainties remain: we do not know if the planet is tidally locked, whether it retains a protective magnetic field, or if any atmosphere persists. K2-332 b's discovery via transit photometry by the Kepler mission makes it an excellent candidate for follow-up atmospheric characterization with future telescopes, potentially revealing whether this distant super-Earth harbors the chemical signatures of life.
What it would be like
K2-332 b is a super-Earth — larger than our planet but likely still rocky or ice-rich. Whether it has a thin atmosphere like Mars or a crushing one like Venus remains unknown.
Surface gravity is about 1.1g — noticeably heavier what you're used to on Earth.
With an equilibrium temperature around -7°C, this planet sits in the temperature range where liquid water could potentially exist on the surface — a key ingredient for life as we know it.
An orbital period of 18 days makes the year 20.6× shorter than Earth's. You'd celebrate your birthday more often here.
Earth comparison
Logarithmic bars so Jupiter-class planets fit the same scale as Earth-size worlds.
Radius2.20R⊕
1/25×Earth = 125×
Mass5.48M⊕
1/10000×Earth = 110000×
Surface gravity1.13g
1/100×Earth = 1100×
Equilibrium temp266 K(-7°C)
0 KEarth 255 K2500 K
Side-by-side with Earth
Temperature in context
Liquid N₂Mars avgEarth eq.Earth sfc.Boiling H₂OVenus
Discovery & orbit
- Method
- Transit
- Year
- 2021
- Facility
- K2
- Semi-major axis
- —
- Period
- 17.71 days
- Eccentricity
- —
- Density
- 2.83 g/cm³
Detected by measuring the tiny dip in starlight as the planet crosses in front of its star.
Low density — probably icy or gas-rich.
Discovered via · Transit
Tiny dip in starlight as the planet crosses in front of its star
A transit photometer watches a star nonstop and measures its brightness to ~0.01%. When a planet passes between us and the star, the star dims briefly — the deeper the dip, the bigger the planet. This is how Kepler and TESS found most known exoplanets.
- Overall share
- ~75% of all confirmed worlds
- Best for
- Earth-to-Neptune-sized planets on short orbits
Hertzsprung–Russell Diagram
Where this host star sits among … exoplanet host stars. The main sequence band runs diagonally — giants and supergiants sit above, white dwarfs below.
OBAFGKMCurrent star
How far is 402 light-years?
- A light beam leaving Earth right now would arrive in 402 years.
- At Voyager 1's speed (17 km/s), the trip would take approximately 7.1 million years.
- A radio signal sent today would arrive in 401.8 years — and the reply wouldn't come back for twice that.
Earth Similarity Index
82/1000 — Nothing like Earth100 — Identical to Earth
ESI combines radius similarity and equilibrium temperature similarity. Earth = 100. Mars ≈ 73. Venus ≈ 44. This score reflects two physical parameters only — not atmosphere, water, or magnetic field.