Sedna
Sedna follows an extremely elongated orbit whose nearest point is still far beyond Neptune, and may belong to the inner Oort Cloud. It is not officially classed as a dwarf planet, nor has its surface been resolved; this inferred texture follows its observed deep-red color and icy spectrum.
Sedna Science file
A red island, · bound for the farthest Solar System
Basic properties
- Distance from the Sun
- 76 to about 937 AU
- Equatorial diameter
- 约 1,000 km
- Orbital period
- About 11,400 Earth years
- Rotation period
- About 10.3 hours (estimated)
- Surface gravity
- About 2% of Earth's (estimated)
- Typical temperature
- About −240°C
- Atmosphere
- Unknown, possibly extremely thin
- Moon system
- No moons discovered
Highlights
More than ten millennia per orbit
Sedna's orbit is extremely eccentric, with perihelion near 76 AU and aphelion close to 1,000 AU.
One of the reddest Solar System bodies
Its deep-red hue may come from complex substances formed as organic molecules in surface ice endure long-term radiation.
Still a dwarf-planet candidate
It is probably nearly round, but its size and shape remain too uncertain for an official dwarf-planet designation.