Discovery | |
---|---|
Discovered by | Annibale de Gasparis |
Discovery site | Naples Obs. |
Discovery date | 2 November 1850 |
Designations | |
(13) Egeria | |
Pronunciation | /ɪˈdʒɪəriə/ [1] |
Named after | Egeria |
Main belt | |
Adjectives | Egerian |
Symbol | (historical) |
Orbital characteristics [2] | |
Epoch 13 January 2016 (JD 2457400.5) | |
Uncertainty parameter 0 | |
Observation arc | 60342 days (165.21 yr) |
Aphelion | 2.7927 AU (417.78 Gm) |
Perihelion | 2.36115 AU (353.223 Gm) |
2.57690 AU (385.499 Gm) | |
Eccentricity | 0.083726 |
4.14 yr (1510.9 d) | |
Average orbital speed | 18.56 km/s |
261.863° | |
0° 14m 17.736s / day | |
Inclination | 16.539° |
43.239° | |
80.294° | |
Earth MOID | 1.43999 AU (215.419 Gm) |
Jupiter MOID | 2.35966 AU (353.000 Gm) |
TJupiter | 3.364 |
Physical characteristics | |
Dimensions | c/a = 0.76±0.06 [3] 214.8×192 [4] |
Mean diameter | 202±3 km [3] 207.6 ± 8.3 km (IRAS) [2] |
Mean radius | 103.82 ± 4.15 km |
Mass | (9.2±2.1)×1018 kg [3] (15.9±4.4)×1018 kg [lower-alpha 1] [5] |
Mean density | 2.13±0.49 g/cm3 [3] 3.4±1.0 g/cm3 [5] |
Equatorial surface gravity | ≈0.0580 m/s2 |
Equatorial escape velocity | ≈0.1098 km/s |
0.2935 d [6] (7.045 h) [2] | |
0.087 [3] 0.0825 ± 0.007 [2] [7] | |
Temperature | ~174 K |
G-type asteroid [2] | |
9.71 to 12.46 [8] | |
6.74 [2] | |
Egeria (minor planet designation: 13 Egeria) is a large main-belt G-type asteroid. [9] It was discovered by Annibale de Gasparis on November 2, 1850. Egeria was named by Urbain Le Verrier, whose computations led to the discovery of Neptune, after the mythological nymph Egeria of Aricia, Italy, the wife of Numa Pompilius, second king of Rome. [10]
The historical symbol for Egeria was a buckler. It is in the pipeline for Unicode 17.0 as U+1CEC6 ( ). [11] [12]
Egeria occulted a star on January 8, 1992. Its disc was determined to be quite circular (217×196 km). On January 22, 2008, it occulted another star, and this occultation was timed by several observers in New Mexico and Arizona, coordinated by the IOTA Asteroid Occultation Program. [4] The result showed that Egeria presented an approximately circular profile to Earth of 214.8×192 km, well in agreement with the 1992 occultation.[ citation needed ] It has also been studied by radar. [13]
In 1988 a search for satellites or dust orbiting this asteroid was performed using the UH88 telescope at the Mauna Kea Observatories, but the effort came up empty. [14] Spectral analysis of Egeria shows it to be unusually high in water content, 10.5–11.5% water by mass. [15] This makes Egeria a prominent candidate for future water-mining ventures.
Eugenia is a large asteroid of the asteroid belt. It is famed as one of the first asteroids to be found to have a moon orbiting it. It was also the second triple asteroid to be discovered, after 87 Sylvia.
216 Kleopatra is a large M-type asteroid with a mean diameter of 120 kilometers and is noted for its elongate bone or dumbbell shape. It was discovered on 10 April 1880 by Austrian astronomer Johann Palisa at the Austrian Naval Pola Observatory, in what is now Pula, Croatia, and was named after Cleopatra, the famous Egyptian queen. It has two small minor-planet moons which were discovered in 2008 and later named Alexhelios and Cleoselene.
Nemausa is a large main-belt asteroid that was discovered on January 22, 1858, by Joseph Jean Pierre Laurent. Laurent made the discovery from the private observatory of Benjamin Valz in Nîmes, France. The house, at 32 rue Nationale in Nîmes, has a plaque commemorating the discovery. With Laurent's permission, Valz named the asteroid after the Celtic god Nemausus, the patron god and namesake of Nîmes during Roman times.
Parthenope is a large, bright main-belt asteroid.
Irene is a large main-belt asteroid, discovered by the English astronomer John Russell Hind on May 19, 1851. It is orbiting the Sun at a distance of 2.585 AU with a period of 4.16 yr and an eccentricity of 0.168. The orbital plane is tilted at an angle of 9.1° to the plane of the ecliptic.
Melpomene is a large, bright main-belt asteroid that was discovered by J. R. Hind on 24 June 1852, and named after Melpomenē, the Muse of tragedy in Greek mythology. Its historical symbol was a dagger over a star; it is in the pipeline for Unicode 17.0 as U+1CECB .
Laetitia is a large main-belt asteroid that was discovered by French astronomer Jean Chacornac on 9 February 1856 and named after Laetitia, a minor Roman goddess of gaiety. The spectrum matches an S-type, indicating a stony (silicate) composition. It is orbiting the Sun with a period of 4.61 years and is spinning on its axis once every 5.1 hours.
Harmonia is a large main-belt asteroid. It was discovered by German-French astronomer Hermann Goldschmidt on March 31, 1856, and named after Harmonia, the Greek goddess of harmony. The name was chosen to mark the end of the Crimean War.
Daphne is a large asteroid from the asteroid belt. It is a dark-surfaced body 174 km in diameter is probably composed of primitive carbonaceous chondrites. The spectra of the asteroid displays evidence of aqueous alteration. It was discovered by H. Goldschmidt on May 22, 1856, and named after Daphne, the nymph in Greek mythology who was turned into a laurel tree. Incorrect orbital calculations initially resulted in 56 Melete being mistaken for a second sighting of Daphne. Daphne was not sighted again until August 31, 1862.
Hestia is a large, dark main-belt asteroid. It is also the primary body of the Hestia clump, a group of asteroids with similar orbits.
Alexandra is a carbonaceous asteroid from the intermediate asteroid belt, approximately 155 kilometers in diameter. It was discovered by German-French astronomer Hermann Goldschmidt on 10 September 1858, and named after the German explorer Alexander von Humboldt; it was the first asteroid to be named after a male.
Melete is a large and dark main belt asteroid. It is a rather unusual P-type asteroid, probably composed of organic rich silicates, carbon and anhydrous silicates, with possible internal water ice. The asteroid orbits the Sun with a period of 4.18 years.
Angelina is an asteroid from the central region of the asteroid belt, approximately 50 kilometers in diameter. It is an unusually bright form of E-type asteroid.
Frigga is a large, M-type, possibly metallic main-belt asteroid. It was discovered by the German-American astronomer C. H. F. Peters on November 12, 1862. The object is named after Frigg, the Norse goddess. The asteroid is orbiting the Sun with a period of 4.36 years and completes a rotation on its axis every nine hours.
Eukrate is a rather large main-belt asteroid. It is dark and probably a primitive carbonaceous body. The asteroid was discovered by Robert Luther on March 14, 1885, in Düsseldorf. It was named after Eucrate, a Nereid in Greek mythology.
Sapientia is a very large Main belt asteroid that was discovered by Johann Palisa on 15 April 1888 in Vienna. It is classified as a C-type asteroid and is probably composed of carbonaceous material. It is named for the Roman personification of wisdom, Sapientia.
Bamberga is one of the largest asteroids in the asteroid belt. It was discovered by Johann Palisa on 25 February 1892 in Vienna. It is one of the top-20 largest asteroids in the asteroid belt. Apart from the near-Earth asteroid Eros, it was the last asteroid which is ever easily visible with binoculars to be discovered.
Dembowska is a large asteroid of the main belt, discovered on 9 December 1892, by the French astronomer Auguste Charlois while working at the observatory in Nice, France. It is named in honor of the Baron Hercules Dembowski, an Italian astronomer who made significant contributions to research on double and multiple stars.
Liguria is a very large main-belt asteroid that was discovered by Auguste Charlois on January 21, 1893, in Nice. It is one of seven of Charlois's discoveries that was expressly named by the Astromomisches Rechen-Institut, and was named for the Italian region.
694 Ekard is a minor planet orbiting the Sun that was discovered by American astronomer Joel Hastings Metcalf on November 7, 1909. The asteroid's name comes from the reverse spelling of Drake University in Des Moines, Iowa, where Seth Barnes Nicholson and his wife calculated its orbit.