Exoplanet · mini-Neptune
K2-18 b
K2-18 b is a mini-Neptune orbiting the star K2-18. Its year lasts 32.9 Earth days. It was discovered in 2015 by the Transit method.
| Host star | K2-18 |
|---|---|
| Distance | 124.0 light-years (38.0 pc) |
| Orbital period | 32.9 days |
| Orbital radius | 0.143 AU |
| Eccentricity | 0.200 |
| Radius | 2.37 R⊕ · 0.211 R♃ |
| Mass | 8.92 M⊕ · 0.0281 M♃ |
| Density | 4.11 g/cm³ |
| Surface gravity | 1.59 × Earth |
| Equilibrium temperature | 284 K (11 °C) |
| Stellar flux received | 1.01 × Earth |
| Discovery method | Transit |
| Discovery year | 2015 |
| Discovered by | K2 |
Habitable zone
Inside its star's habitable zone: it receives enough light for liquid water to exist on its surface under a suitable atmosphere.
Its star in the sky
In the planet's sky its star is a disc 1.5° across: 2.9 times the Sun as we see it from Earth.
In the sky
A telescope is needed to see it: its apparent magnitude is 13.47. Visible from the whole Northern Hemisphere and south to latitude 82° S. It stands highest at midnight in March, the best time to observe it.
Light's journey
The light you see tonight set out around the year 1902. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 2.2 million years.
Planets in the same system
- K2-18 c 8.96-day orbit · 2.65 R⊕
Data: NASA Exoplanet Archive, PSCompPars. Its look in the simulation is a rendering based on the measured radius, mass and temperature.