Exoplanet · Neptune-like planet
Kepler-397 c
Kepler-397 c is a Neptune-like planet orbiting the star Kepler-397. Its year lasts 135 Earth days. It was discovered in 2014 by the Transit method.
| Host star | Kepler-397 |
|---|---|
| Distance | 3,160 light-years (969.0 pc) |
| Orbital period | 135 days |
| Orbital radius | 0.48 AU |
| Eccentricity | 0.000 |
| Radius | 6.18 R⊕ · 0.551 R♃ |
| Mass | 31.6 M⊕ · 0.0994 M♃ (estimated from the radius) |
| Density | 0.736 g/cm³ |
| Equilibrium temperature | 295 K (22 °C) |
| Stellar flux received | 1.8 × Earth |
| Discovery method | Transit |
| Discovery year | 2014 |
| Discovered by | Kepler |
Habitable zone
Inside the inner edge of the habitable zone: it receives 1.8 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 0.85° across: 1.6 times the Sun as we see it from Earth.
In the sky
A telescope is needed to see it: its apparent magnitude is 16.36. Visible from the whole Northern Hemisphere and south to latitude 48° S. North of latitude 48° 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 1135 BC. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 56 million years.
Planets in the same system
- Kepler-397 b 22.3-day orbit · 2.46 R⊕
Data: NASA Exoplanet Archive, PSCompPars. Its look in the simulation is a rendering based on the measured radius, mass and temperature.