Exoplanet · Neptune-like planet
GJ 581 b
GJ 581 b is a Neptune-like planet orbiting the star GJ 581. Its year lasts 5.37 Earth days. It was discovered in 2005 by the Radial Velocity method.
| Host star | GJ 581 |
|---|---|
| Distance | 20.5 light-years (6.30 pc) |
| Orbital period | 5.37 days |
| Orbital radius | 0.0399 AU |
| Eccentricity | 0.034 |
| Radius | 4.79 R⊕ · 0.427 R♃ |
| Mass | 20.5 M⊕ · 0.0645 M♃ |
| Density | 1.02 g/cm³ |
| Surface gravity | 0.893 × Earth |
| Equilibrium temperature | 464 K (191 °C) |
| Stellar flux received | 7.77 × Earth |
| Discovery method | Radial Velocity |
| Discovery year | 2005 |
| Discovered by | La Silla Observatory |
Habitable zone
Inside the inner edge of the habitable zone: it receives 7.77 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 4° across: 7.6 times the Sun as we see it from Earth.
In the sky
A telescope is needed to see it: its apparent magnitude is 10.57. Visible from the whole Southern Hemisphere and north to latitude 82° N. It stands highest at midnight in May, 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 364 thousand years.
Planets in the same system
Data: NASA Exoplanet Archive, PSCompPars. Its look in the simulation is a rendering based on the measured radius, mass and temperature.