Exoplanet · Neptune-like planet
Kepler-4 b
Kepler-4 b is a Neptune-like planet orbiting the star Kepler-4. Its year lasts 3.21 Earth days. It was discovered in 2009 by the Transit method.
| Host star | Kepler-4 |
|---|---|
| Distance | 1,591 light-years (487.9 pc) |
| Orbital period | 3.21 days |
| Orbital radius | 0.0456 AU |
| Eccentricity | 0.000 |
| Radius | 4 R⊕ · 0.357 R♃ |
| Mass | 24.5 M⊕ · 0.077 M♃ |
| Density | 1.91 g/cm³ |
| Surface gravity | 1.53 × Earth |
| Equilibrium temperature | 1,650 K (1,377 °C) |
| Stellar flux received | 1,250 × Earth |
| Discovery method | Transit |
| Discovery year | 2009 |
| Discovered by | Kepler |
Habitable zone
Inside the inner edge of the habitable zone: it receives 1,250 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: 32 times the Sun as we see it from Earth.
In the sky
A telescope is needed to see it: its apparent magnitude is 12.29. Visible from the whole Northern Hemisphere and south to latitude 40° S. North of latitude 40° N it never sets. It stands highest at midnight in July, the best time to observe it.
Light's journey
The light you see tonight set out around the year 435. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 28 million years.
Data: NASA Exoplanet Archive, PSCompPars. Its look in the simulation is a rendering based on the measured radius, mass and temperature.