Nemausa (

minor planet designation A formal minor-planet designation is, in its final form, a number–name combination given to a minor planet (asteroid, centaur, trans-Neptunian object and dwarf planet but not comet). Such designation always features a leading number (catalog or ...

: 51 Nemausa) is a large

main-belt The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

that was discovered on January 22, 1858, by

Joseph Jean Pierre Laurent Joseph Jean Pierre Laurent (or Joseph Laurent) (died 1900) was a French amateur astronomer and chemist who discovered the asteroid 51 Nemausa in 1858, for which he was a recipient of the Lalande Prize awarded by the French Academ ...

. Laurent made the discovery from the private observatory of

Benjamin Valz Jean Elias Benjamin Valz (May 27, 1787 – April 22, 1867) was a French astronomer. He was born in Nîmes and trained as an engineer. He was the son of politician Jean Valz and the grandson of the doctor, meteorologist and naturalist Pierre ...

Nîmes Nîmes ( , ; oc, Nimes ; Latin: ''Nemausus'') is the prefecture of the Gard department in the Occitanie region of Southern France. Located between the Mediterranean Sea and Cévennes, the commune of Nîmes has an estimated population of 148,5 ...

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

. 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 Celtic, Celtics or Keltic may refer to: Language and ethnicity *pertaining to Celts, a collection of Indo-European peoples in Europe and Anatolia **Celts (modern) *Celtic languages **Proto-Celtic language * Celtic music *Celtic nations Sports Fo ...

god

Nemausus Deus Nemausus is often said to have been the Celtic patron god of Nemausus (Nîmes). The god does not seem to have been worshipped outside this locality. The city certainly derives its name from Nemausus, which was perhaps the sacred wood in which ...

, the patron god and namesake of Nîmes during Roman times. Based upon its spectrum, this is listed as a

C-type asteroid C-type (carbonaceous) asteroids are the most common variety, forming around 75% of known asteroids. They are volatile-rich and distinguished by a very low albedo because their composition includes a large amount of carbon, in addition to rocks ...

in the

Tholen classification An asteroid spectral type is assigned to asteroids based on their emission spectrum, color, and sometimes albedo. These types are thought to correspond to an asteroid's surface composition. For small bodies that are not internally differentiated ...

taxonomy, and as a Cgh by Bus and Binzel (2002). This indicates a composition similar to

carbonaceous chondrite Carbonaceous chondrites or C chondrites are a class of chondritic meteorites comprising at least 8 known groups and many ungrouped meteorites. They include some of the most primitive known meteorites. The C chondrites represent only a small prop ...

meteorites. Absorption features in the spectrum indicate the presence of

phyllosilicates Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, silica (silicon dioxide, ) is usually consid ...

. It may have a water content of about 14%. The first stellar

occultation An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks ...

was observed on August 17, 1979, from the Gissar and Alma-Ata observatories produced two chords which were used to estimate a diameter of 150 km for the asteroid. This is close to the present-day estimate of 147.9 km. Since then 51 Nemausa has been observed 20 times in stellar occultation. Light curve inversion mode
DAMIT1065
is a good match to a seven-chord occultation observed on 3rd September 2016, from which an equivalent Volume mean diameter of 146.4km, and an equivalent Surface mean diameter of 150.3 km was obtained.

Lightcurve In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequ ...

data suggests that it may have a small

moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

.Other reports of asteroid/TNO companions
/ref> Nemausa has been studied by

radar Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...

References

External links

* * {{DEFAULTSORT:000051 Background asteroids Nemausa Nemausa Objects observed by stellar occultation CU-type asteroids (Tholen) Ch-type asteroids (SMASS) 18580122

See also

References

External links