Sedna

Also known as (90377) 2003 VB12, (90377) Sedna 2003, 90377 Sedna, Sedna (dwarf planet)

dwarf planet in the outermost Solar system

AI overview

Sedna is a dwarf planet located in the far reaches of our Solar System, beyond the orbits of Neptune and Pluto. Scientists study it because its distant and unusual orbit provides clues about the structure and history of the outer Solar System.

AI-generated from the Wikipedia summary — may contain errors.

Wikidata facts

Diameter: 1025
Orbital period: 4705404.650143452
Image: Sedna PRC2004-14d.jpg

Show 20 more facts

Commons category: 90377 Sedna
provisional designation: 2003 VB12
time of discovery or invention: 2003-11-14
orbital inclination: 11.92591698495942
Commons gallery: 90377 Sedna
albedo: 0.07
absolute magnitude: 1.49
mean anomaly: 358.6072551587332
argument of periapsis: 311.0099164178038
temperature: 12
color index: 0.78
longitude of ascending node: 144.4786863232386
semi-major axis of an orbit: 549.5396510704963
apparent magnitude: 21.12
Unicode character: ⯲
rotation period: 10.273
orbital eccentricity: 0.8612973329749037
periapsis: 76.22261523951863
apoapsis: 1022.856686901474
time of periapsis: 2479204.466812667

Sources (10)

via Wikidata · CC0

~27 min read

Article

Sedna (minor-planet number 90377) is a dwarf planet in the outermost reaches of the Solar System, orbiting the Sun far beyond the orbit of Neptune. It was discovered in 2003, and is roughly 1,000 km in diameter. Spectroscopic analysis has revealed its surface to be a mixture of the solid ices of water, carbon dioxide, and ethane, along with sedimentary deposits of methane-derived, reddish-colored tholins, a chemical makeup similar to the surfaces of other trans-Neptunian objects. Sedna is not expected to have a substantial atmosphere. Within the range of uncertainty, it is tied with Ceres in the asteroid belt as the largest dwarf planet not known to have a moon. Owing to its lack of known moons, Sedna's mass and density remain unknown.

Sedna takes approximately 11,400 years to complete one orbit around the Sun. Its orbit is one of the widest known in the Solar System. Its aphelion is located 937 astronomical units (AU) away, about 19 times farther than that of Pluto. Sedna's orbit is also one of the most elliptical discovered, with an eccentricity of 0.85. As of 2026, Sedna is 83.0 AU (12.4 billion km) from the Sun, 2.5 times as far away as Neptune.