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 | 214.8 km × 192 km [3] |
202±3 km [4] 207.6 ± 8.3 km (IRAS) [2] | |
Flattening | 0.24 [lower-alpha 1] |
Mass | (9.2±2.1)×1018 kg [4] (15.9±4.4)×1018 kg [lower-alpha 2] [5] |
Mean density | 2.13±0.49 g/cm3 [4] 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 [4] 0.049 ± 0.028 [2] [7] | |
Temperature | ~174 K |
G-type asteroid [2] | |
9.71 to 12.46 [8] | |
6.92 [2] | |
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. [3] 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.
16 Psyche is a large M-type asteroid, which was discovered by the Italian astronomer Annibale de Gasparis, on 17 March 1852 and named after the Greek goddess Psyche. The prefix "16" signifies that it was the sixteenth minor planet in order of discovery. It is the largest and most massive of the M-type asteroids, and one of the dozen most massive asteroids. It has a mean diameter of approximately 220 kilometers (140 mi) and contains about one percent of the mass of the asteroid belt. It was thought to be the exposed core of a protoplanet, but recent observations cast doubt on that hypothesis. Psyche will be explored by NASA, with a spacecraft of the same name, marking the first time a manmade object will journey to a metallic asteroid, launched on 13 October 2023, with an expected arrival in 2029.
51 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.
7 Iris is a large main-belt asteroid and possible remnant planetesimal orbiting the Sun between Mars and Jupiter. It is the fourth-brightest object in the asteroid belt. 7 Iris is classified as an S-type asteroid, meaning that it has a stony composition.
9 Metis is one of the larger main-belt asteroids. It is composed of silicates and metallic nickel-iron, and may be the core remnant of a large asteroid that was destroyed by an ancient collision. Metis is estimated to contain just under half a percent of the total mass of the asteroid belt.
11 Parthenope is a large, bright main-belt asteroid.
12 Victoria is a large main-belt asteroid, orbiting the Sun with a period of 3.56 years and an eccentricity of 0.221. It is a stony (S-type) asteroid, about 112–124 km across with an albedo of 0.18 and a rotation period of 8.66 hours. Victoria has been observed to occult a star three times since its discovery. Radar and speckle interferometry observations show that the shape of Victoria is elongated, and it is suspected to be a binary asteroid, with a moon of irregular shape.
14 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.
18 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 .
19 Fortuna is one of the largest main-belt asteroids. It has a composition similar to 1 Ceres: a darkly colored surface that is heavily space-weathered with the composition of primitive organic compounds, including tholins.
20 Massalia is a stony asteroid and the parent body of the Massalia family located in the inner region of the asteroid belt, approximately 145 kilometers in diameter. Discovered by Italian astronomer Annibale de Gasparis on 19 September 1852, it was named for the Latin name of the French city of Marseille, from which the independent discover Jean Chacornac sighted it the following night. It was the first asteroid that was not assigned an iconic symbol by its discoverer.
26 Proserpina is a main-belt asteroid discovered by German astronomer R. Luther on May 5, 1853. It is named after the Roman goddess Proserpina, the daughter of Ceres and the Queen of the Underworld. Another main-belt asteroid, 399 Persephone, discovered in 1895, is named after her Greek counterpart. Its historical symbol was a star inside a pomegranate; it is in the pipeline for Unicode 17.0 as U+1CECD .
28 Bellona is a large main-belt asteroid. It was discovered by German astronomer R. Luther on March 1, 1854, and named after Bellōna, the Roman goddess of war; the name was chosen to mark the beginning of the Crimean War. Its historical symbol was Bellona's whip and spear; it is in the pipeline for Unicode 17.0 as U+1CECE .
29 Amphitrite is one of the largest S-type asteroids, approximately 200 kilometers in diameter, and probably fifth largest after Eunomia, Juno, Iris and Herculina.
35 Leukothea is a large, dark asteroid from the asteroid belt. It was discovered by German astronomer Karl Theodor Robert Luther on April 19, 1855, and named after Leukothea, a sea goddess in Greek mythology. Its historical symbol was a pharos ; it is in the pipeline for Unicode 17.0 as U+1CED0 .
39 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.
40 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.
41 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.
77 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.
275 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.
324 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.