24 Themis (thee'-mis, them'-is) is one of the largest Main belt asteroids. It is also the largest member of Themistian asteroid family.

24 Themis

Discovery A
Discoverer	Annibale de Gasparis
Discovery date	April 5, 1853
Alternate designations	1947 BA; 1955 OH B
Category	Main belt (Themis)
Orbital elements C D
Epoch August 18, 2005 (JD 2453600.5)
Eccentricity (e)	0.132
Semi-major axis (a)	468.226 Gm (3.130 AU)
Perihelion (q)	406.202 Gm (2.715 AU)
Aphelion (Q)	530.250 Gm (3.545 AU)
Orbital period (P)	2022.524 d (5.54 a)
Mean orbital speed	16.76 km/s
Inclination (i)	0.760°
Longitude of the ascending node (Ω))	35.992°
Argument of perihelion (ω)	107.989°
Mean anomaly (M)	185.968°
Physical characteristics
Dimensions	228 km
Mass	5.75—1019 kg [1]
Density	9.6 g/cm³
Surface gravity	0.3059 m/s²
Escape velocity	0.2641 km/s
Rotation period	0.34892 d (8 h 23 min) [2] [3]
Spectral class	C [4]
Absolute magnitude	7.08
Albedo	0.067 [5]
Mean surface temperature	~159 K

It was discovered by Annibale de Gasparis on April 5, 1853. The mass and diameter appearing in the table are from separate sources, and combining them gives an unusually large density, which is most probably wrong. The mass has very likely been overestimated by a factor of at least five times.

It is named after Themis, the personification of divine order, law and custom in Greek mythology.

Themis was also the name given to the spurious lost "tenth" satellite of Saturn that William Henry Pickering believed he had found in 1905. [6]

… | Previous asteroid | 24 Themis | Next asteroid | …

The minor planets

Vulcanoids | Main belt | Groups and families | Near-Earth objects | Jupiter Trojans

Centaurs | Damocloids | Comets | Trans-Neptunians (Kuiper belt | Scattered disc | Oort cloud)

For other objects and regions, see: Binary asteroids, Asteroid moons and the Solar system

For a complete listing, see: List of asteroids. For pronunciation, see: Pronunciation of asteroid names.