90482 Orcus Facts for Kids

Quick facts for kids
90482 Orcus
Discovery

Discovered by	M. Brown, C. Trujillo, D. Rabinowitz
Discovery date	February 17, 2004
Designations
Alternative names	2004 DW
Minor planet category	Plutino
Orbital characteristics
Epoch November 30, 2008 (JD 2 454 800)
Aphelion	7 188.17 Gm (48.05 AU)
Perihelion	4 535.80 Gm (30.32 AU)
Semi-major axis	5 862.44 Gm (39.188 AU)
Eccentricity	0.226 18
Orbital period	89 606 d (245.33 yr)
Average orbital speed	4.68 km/s
Mean anomaly	164.68°
Inclination	20.593°
Longitude of ascending node	268.722°
Argument of perihelion	72.474°
Known satellites	1 (92-432 km)
Physical characteristics
Dimensions	946.3 ^+74.1_−72.3 km (diameter)
Mass	~7.5×10²⁰ kg
Mean density	~1.5 g/cm³ (assumed)
Surface gravity	~0.2 m/s²
Escape velocity	~0.44 km/s
Rotation period	13.19h
Albedo	19.75 ^+3.40_−2.76 %
Temperature	~45 K
Spectral type	B-V=0.68; V-R=0.37
Apparent magnitude	19.1 (opposition)
Absolute magnitude (H)	2.3

90482 Orcus is a dwarf planet that lives in the Kuiper belt. The Kuiper belt is a huge ring of icy objects beyond Neptune. Orcus was first called 2004 DW when it was found.

Three scientists named Michael Brown, Chad Trujillo, and David Rabinowitz discovered Orcus. They found it on February 17, 2004. Interestingly, it had been seen in older pictures from November 8, 1951, but wasn't recognized as a dwarf planet then.

Orcus is special because it moves around the Sun in a way similar to Pluto. It has an orbital resonance with Neptune. This means that for every two times Neptune goes around the Sun, Orcus goes around three times. But here's the cool part: Orcus always stays on the opposite side of the Sun from Pluto!

Orcus's Moon

Orcus has its own moon! This moon was discovered on February 22, 2007.

Scientists found the moon very close to Orcus. They used special tools to measure its brightness. Based on how bright it is, they think the moon is about 220 kilometers (about 137 miles) wide. They believe this moon might be a smaller object from the Kuiper belt that Orcus's gravity pulled in.

The Solar System

Sun • Heliosphere	Planets ☾ = moon(s) ∅ = rings		Mercury	Venus	Earth ☾	Mars ☾

			Jupiter ☾ ∅	Saturn ☾ ∅	Uranus ☾ ∅	Neptune ☾ ∅

	Dwarf planets		Ceres	Pluto ☾	Haumea ☾	Makemake

			Eris ☾

	Small Solar System bodies	Asteroids (minor planets)	Groups and families: Vulcanoids · Near-Earth asteroids · Asteroid belt Jupiter Trojans · Centaurs · Neptune Trojans · Asteroid moons · Meteoroids · Pallas · Juno · Vesta · Hygiea · Interamnia · Europa
		Asteroids (minor planets)	See also the list of asteroids.

		Trans- Neptunians	Kuiper belt – Plutinos: Orcus · Ixion – Cubewanos: Varuna · Quaoar · Huya
		Trans- Neptunians	Scattered disc: Sedna

		Comets	Periodic comets and non-periodic comets Damocloids · Oort cloud
See also the list of solar system objects

Images for kids

Discovery image of Orcus taken in 2004
Orcus compared to Earth and the Moon
Long-exposure photograph of Orcus at visual magnitude 19.2
Orcus and Vanth imaged by Hubble in 2006

90482 Orcus facts for kids

Orcus's Moon

Images for kids

See also