Cosmic Scale
55 Cancri e
Lava super-Earth · 41 light-years
How big is 55 Cancri e?
55 Cancri e is about 23,950 km across.
See 55 Cancri e in 3D, at true scale
55 Cancri e is a super-Earth so close to its star that its year lasts 18 hours and its day side may be an ocean of magma. The James Webb telescope found signs of a real atmosphere there in 2024 — surprising for a world that hot.
At a glance
| Diameter | 23,950 km |
|---|---|
| Mass | 4.77 × 10²⁵ kg |
| Diameter compared with Earth | 1.88 × Earth |
| Distance | 41 light-years |
| Year | 18 hours |
| Day side | About 2,400 °C |
Good to know
- It was once suggested to be a diamond planet, if its interior were carbon-rich; later work made that less likely.
- Its star is bright enough to see with the naked eye, which is rare for a planet host.
- The atmosphere may be constantly resupplied by gas bubbling out of the magma.
- Next smaller: Kepler-452b · 20,770 km
- Next larger: Neptune · 49,240 km