K2-331 is 690 light-years from the Sun. The NASA Exoplanet Archive lists 2 planets around this 5,994 K star; the first was found in 2021 by transit (K2).
Fly there in 3DK2-331 b goes round its star every 9.40 days, 9 times as often as Mercury goes round the Sun.
Where the archive gives only a period or only an orbit size, the other is worked out from Kepler’s third law with the star’s mass.
| Surface temperature | 5,994 K |
| Mass | 1.1 solar masses |
| Radius | 1.06 solar radii |
| Luminosity | 1.147 times the Sun |
| Apparent magnitude | 11.305 |
| Distance from the Sun | 689.6 light-years (211.4 parsecs) |
| Position (J2000) | RA 132.7376°, Dec 13.1703° |
| Constellation | Cancer |
| Planet | Year | Orbit | Radius | Mass | Found |
|---|---|---|---|---|---|
| K2-331 b | 9.40 days | 0.0900 AU from Kepler’s law | 1.79 R⊕ | 3.86 M⊕ estimated | Transit, 2021 |
| K2-331 c | 23.0 days | 0.163 AU from Kepler’s law | 2.72 R⊕ | 7.85 M⊕ estimated | Transit, 2021 |
Values are the NASA Exoplanet Archive’s composite parameters. A radius marked estimated comes from a mass–radius relation; a mass marked minimum is M sin i. Planet sizes and colours in the 3D view are renderings: none of these worlds has been photographed as more than a point of light.
For a star of 5,994 K, 1.1 times as bright as the Sun, the habitable zone, where starlight could keep water liquid on a rocky surface, runs from about 1.00 to 1.76 AU. None of its known planets orbits inside it. The zone says how much starlight arrives, not whether a planet has water or air. The edges follow Kopparapu et al. (2014), as the 3D view draws them.
The light you see left 690 years ago, around 1340.