K2-381 is 475 light-years from the Sun. The NASA Exoplanet Archive lists 3 planets around this 4,473 K star; the first was found in 2022 by transit (K2).
Fly there in 3DK2-381 b goes round its star every 7.94 days, 11 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 | 4,473 K |
| Mass | 0.754 solar masses |
| Radius | 0.675 solar radii |
| Luminosity | 0.1823 times the Sun |
| Apparent magnitude | 12.883 |
| Distance from the Sun | 475.2 light-years (145.7 parsecs) |
| Position (J2000) | RA 288.0268°, Dec -21.0076° |
| Constellation | Sagittarius |
| Planet | Year | Orbit | Radius | Mass | Found |
|---|---|---|---|---|---|
| K2-381 b | 7.94 days | 0.0709 AU from Kepler’s law | 1.075 R⊕ | 1.26 M⊕ estimated | Transit, 2022 |
| K2-381 c | 16.0 days | 0.113 AU from Kepler’s law | 2 R⊕ | 4.66 M⊕ estimated | Transit, 2022 |
| K2-381 d | 26.8 days | 0.160 AU from Kepler’s law | 1.689 R⊕ | 3.5 M⊕ estimated | Transit, 2022 |
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 4,473 K, 0.18 times as bright as the Sun, the habitable zone, where starlight could keep water liquid on a rocky surface, runs from about 0.43 to 0.80 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 475 years ago, around 1550.