Laetitia (

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 ...

: 39 Laetitia) 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 by French astronomer

Jean Chacornac Jean Chacornac (21 June 1823 – 23 September 1873) was a French astronomer and discoverer of a comet and several asteroids. He was born in Lyon and died in Saint-Jean-en-Royans, southeastern France. Working in Marseille and Paris, he discov ...

on 9 February 1856 and named after Laetitia, a minor

Roman Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of ancient Rome *''Epistle to the Romans'', shortened to ''Romans'', a letter ...

goddess of

gaiety Gaiety or Gayety may refer to: * Gaiety (mood), the state of being happy * Gaiety Theatre (disambiguation) * ''USS Gayety (AM-239'', former name of the ship ''BRP Magat Salamat (PS-20)'' See also *Gaiety Girls Gaiety Girls were the chorus girl ...

. The spectrum matches an S-type, indicating a stony (silicate) composition. It is orbiting the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

with a period of and is spinning on its axis once every 5.1 hours. Photometric observations of this asteroid gathered between 1968–74 were used to build a

light curve 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 ...

that provided shape and rotation information. It has the general shape of an elongated triaxial

ellipsoid An ellipsoid is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a surface that may be defined as the ...

with ratios between the lengths of the axes equal to 15:9:5. Major surface features are on a scale of 10 km and the surface color does not vary significantly across the surface. In the

ecliptic coordinate system The ecliptic coordinate system is a celestial coordinate system commonly used for representing the apparent positions, orbits, and pole orientations of Solar System objects. Because most planets (except Mercury) and many small Solar System bodi ...

, the pole of rotation is estimated to be oriented to the coordinates (λ₀, β₀) = (, ). In 1988 a search for satellites or dust orbiting this asteroid was performed using the

UH88 The University of Hawai'i 88-inch (2.24-meter) telescope—called UH88, UH2.2, or simply 88 by members of the local astronomical community—is situated at the Mauna Kea Observatories and operated by the University's Institute for Astronomy. It ...

telescope at the

Mauna Kea Observatories The Mauna Kea Observatories (MKO) are a group of independent astronomical research facilities and large telescope observatories that are located at the summit of Mauna Kea on the Big Island of Hawaiʻi, United States. The facilities are located ...

, but the effort came up empty. Photometric observations collected during 2006–08 were used to measure time variations of the asteroid light curve. This data suggests that the asteroid may have a complex shape or it could be a

binary asteroid A binary asteroid is a system of two asteroids orbiting their common barycenter. The binary nature of 243 Ida was discovered when the Galileo spacecraft flew by the asteroid in 1993. Since then numerous binary asteroids and several triple a ...

system. Observations of an

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 ...

on 21 March 1998, produced several

chords Chord may refer to: * Chord (music), an aggregate of musical pitches sounded simultaneously ** Guitar chord a chord played on a guitar, which has a particular tuning * Chord (geometry), a line segment joining two points on a curve * Chord (as ...

indicating an ellipsoidal cross-section of .

References

External links

* * {{DEFAULTSORT:000039 S-type asteroids (SMASS) S-type asteroids (Tholen) Background asteroids Laetitia Laetitia Laetitia 18560208 Objects observed by stellar occultation