Exoplanet · mini-Neptune
GJ 338 B b
GJ 338 B b is a mini-Neptune orbiting the star GJ 338 B. Its year lasts 24.4 Earth days. It was discovered in 2020 by the Radial Velocity method.
| Host star | GJ 338 B |
|---|---|
| Distance | 20.7 light-years (6.33 pc) |
| Orbital period | 24.4 days |
| Orbital radius | 0.142 AU |
| Eccentricity | 0.109 |
| Radius | 3.25 R⊕ · 0.29 R♃ |
| Mass (minimum) | 10.6 M⊕ · 0.0334 M♃ |
| Density | 1.7 g/cm³ |
| Equilibrium temperature | 391 K (118 °C) |
| Stellar flux received | 3.93 × Earth |
| Discovery method | Radial Velocity |
| Discovery year | 2020 |
| Discovered by | Calar Alto Observatory |
Habitable zone
Inside the inner edge of the habitable zone: it receives 3.93 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 2.2° across: 4.1 times the Sun as we see it from Earth.
In the sky
Too faint for the naked eye (magnitude 7.70); binoculars will find it. Visible from the whole Northern Hemisphere and south to latitude 37° S. North of latitude 37° N it never sets. It stands highest at midnight in February, the best time to observe it.
Light's journey
The light you see tonight set out around the year 2005. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 366 thousand years.
Data: NASA Exoplanet Archive, PSCompPars. Its look in the simulation is a rendering based on the measured radius, mass and temperature.