Exoplanet · mini-Neptune
K2-278 b
K2-278 b is a mini-Neptune orbiting the star K2-278. Its year lasts 3.33 Earth days. It was discovered in 2018 by the Transit method.
| Host star | K2-278 |
|---|---|
| Distance | 2,565 light-years (786.4 pc) |
| Orbital period | 3.33 days |
| Orbital radius | 0.0488 AU |
| Radius | 2.98 R⊕ · 0.266 R♃ |
| Mass | 9.17 M⊕ · 0.0289 M♃ (estimated from the radius) |
| Density | 1.9 g/cm³ |
| Equilibrium temperature | 1,711 K (1,438 °C) |
| Stellar flux received | 1,050 × Earth |
| Discovery method | Transit |
| Discovery year | 2018 |
| Discovered by | K2 |
Habitable zone
Inside the inner edge of the habitable zone: it receives 1,050 times the light the Earth does, too hot to keep liquid water on its surface.
Its star in the sky
In the planet's sky its star is a disc 17° across: 33 times the Sun as we see it from Earth.
In the sky
A telescope is needed to see it: its apparent magnitude is 13.45. Visible from the whole Southern Hemisphere and north to latitude 75° N. South of latitude 75° S it never sets. It stands highest at midnight in April, the best time to observe it.
Light's journey
The light you see tonight set out around 540 BC. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 46 million years.
Data: NASA Exoplanet Archive, PSCompPars. Its look in the simulation is a rendering based on the measured radius, mass and temperature.