13 Egeria is a large main-belt

Asteroid belt

The asteroid belt is the region of the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets...

 G-type

G-type asteroid

G-type asteroids are a relatively uncommon type of carbonaceous asteroid. The most notable asteroid in this class is 1 Ceres.- Characteristics :Generally similar to the C-type objects, but containing a strong ultraviolet absorption feature below 0.5 μm...

 asteroid

Asteroid

Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...

.

It was discovered by A. de Gasparis

Annibale de Gasparis

Annibale de Gasparis was an Italian astronomer. From 1864 to 1889 he was the director of the Astronomical Observatory of Capodimonte in Naples.He won the Gold Medal of the Royal Astronomical Society in 1851....

 on November 2, 1850, and was named by Urbain J. J. Le Verrier, whose computations led to the discovery of Neptune

Neptune

Neptune is the eighth and farthest planet from the Sun in the Solar System. Named for the Roman god of the sea, it is the fourth-largest planet by diameter and the third largest by mass. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times...

. Egeria

Egeria (mythology)

Egeria was a nymph attributed a legendary role in the early history of Rome as a divine consort and counselor of the Sabine second king of Rome, Numa Pompilius, to whom she imparted laws and rituals pertaining to ancient Roman religion...

 was a goddess

Goddess

A goddess is a female deity. In some cultures goddesses are associated with Earth, motherhood, love, and the household. In other cultures, goddesses also rule over war, death, and destruction as well as healing....

 (other sources say a nymph

Nymph

A nymph in Greek mythology is a female minor nature deity typically associated with a particular location or landform. Different from gods, nymphs are generally regarded as divine spirits who animate nature, and are usually depicted as beautiful, young nubile maidens who love to dance and sing;...

) of Aricia

Aricia

Aricia can refer to:*Aricia, a genus of gossamer-winged butterflies usually included in Aricia *Aricia , historical figure in ancient Britain*Aricia , minor figure in Greek mythology*Aricia, Italy...

, in Italy

Italy

Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

, and the wife of Numa Pompilius

Numa Pompilius

Numa Pompilius was the legendary second king of Rome, succeeding Romulus. What tales are descended to us about him come from Valerius Antias, an author from the early part of the 1st century BC known through limited mentions of later authors , Dionysius of Halicarnassus circa 60BC-...

, second king of Rome

Rome

Rome is the capital of Italy and the country's largest and most populated city and comune, with over 2.7 million residents in . The city is located in the central-western portion of the Italian Peninsula, on the Tiber River within the Lazio region of Italy.Rome's history spans two and a half...

.

Egeria occulted

Occultation

An occultation is an event that occurs when one object is hidden by another object that passes between it and the observer. The word is used in astronomy . It can also refer to any situation wherein an object in the foreground blocks from view an object in the background...

 a star

Star

A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

 on January 8, 1992. The former's disc was determined to be quite circular (217×196 km).

On January 22, 2008, Egeria occulted

Occultation

An occultation is an event that occurs when one object is hidden by another object that passes between it and the observer. The word is used in astronomy . It can also refer to any situation wherein an object in the foreground blocks from view an object in the background...

  another star

Star

A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

 and this occultation was timed by several observers in New Mexico

New Mexico

New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...

 and Arizona

Arizona

Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

, coordinated by the IOTA Asteroid Occultation Program. The data was entered into the OCCULT4 estimation and visualization program written by Dave Herald of Canberra, Australia. The result showed that Egeria presented an approximately circular profile to Earth of 214.8x192 km, well in agreement with the 1992 occultation.

High water content

Spectral analysis of Egeria shows it to be unusually high in water content, between 10.5-11.5% water by mass. This makes Egeria a prominent candidate for future water-mining ventures.

External links

• Orbital simulation from JPL (Java) / JPL Horizons Ephemeris (displays Elong from Sun and V mag
  Apparent magnitude
  The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
  
  for 2011)