24 Themis
Three-dimensional model of 24 Themis created based on light-curve inversions.
|
|
| Discovery | |
|---|---|
| Discovered by | Annibale de Gasparis |
| Discovery date | 5 April 1853 |
| Designations | |
| MPC designation | (24) Themis |
| Pronunciation | /ˈθiːmᵻs/ THEE-məs |
|
Named after
|
Themis |
| 1947 BA; 1955 OH | |
| Main belt (Themis) | |
| Adjectives | Themistian |
| Orbital characteristics | |
| Epoch 23 July 2010 (JD 2455400.5) | |
| Aphelion | 529.4 Gm (3.539 AU) |
| Perihelion | 406.8 Gm (2.719 AU) |
| 468.1 Gm (3.129 AU) |
|
| Eccentricity | 0.1310 |
| 2021 d (5.54 yr) | |
|
Average orbital speed
|
16.76 km/s |
| 146.6° | |
| Inclination | 0.7595° |
| 35.99° | |
| 107.7° | |
| Physical characteristics | |
| Dimensions | 198±20 km |
| Mass |
(1.13±0.43)×1019 kg 2.3×1019 kg |
|
Mean density
|
2.78±1.35 g/cm3 |
| 0.15+0.08 −0.07 m/s2 |
|
| 87+15 −20 m/s |
|
| 0.34892 d (8 h 23 min) | |
| Albedo | 0.067 |
| Temperature | ~159 K |
|
Spectral type
|
C/B (B-V=0.68) |
| 7.08 | |
24 Themis (THEE-məs) is one of the largest asteroids in the asteroid belt. It is also the largest member of the Themis family. It was discovered by Annibale de Gasparis on 5 April 1853. It is named after Themis, the personification of natural law and divine order in Greek mythology.
Not to be confused with 269 Justitia, named for Justitia, Themis' Roman name.
24 Themis was discovered on 5 April 1853 by Annibale de Gasparis of Naples, though it was given its name by fellow Italian astronomer Angelo Secchi. The asteroid was named after Themis, the Greek goddess of law. Gravitational perturbations in the orbit of Themis were used to calculate the mass of Jupiter as early as 1875.
On 24 December 1975, 24 Themis had a close encounter with 2296 Kugultinov with a minimum distance of 0.016 AU (2.4×106 km). By analyzing the perturbation of Kugultinov's orbit due to the gravitational pull of Themis, the mass of Themis was determined to be approximately 2.89×10−11 solar masses (9.62×10−6 Earth masses).
Themis is in an elliptical orbit around the Sun with an eccentricity of 0.1306 and an inclination of 0.76°. It has an orbital period of 5.54 years. The distance between Themis and the Sun ranges from 2.71 AU at perihelion and 3.55 AU at aphelion, with a mean distance of 3.1302 AU. Themis is part of the Themis family of asteroids, which is located in the outer part of the main belt. The family consists of a core of large objects surrounded by a cloud of smaller objects; 24 Themis is a member of the core.
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