Lachesis (

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 ...

: 120 Lachesis) is a large

main-belt asteroid 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 ...

. It was discovered by French astronomer

Alphonse Borrelly Alphonse Louis Nicolas Borrelly (December 8, 1842 – February 28, 1926) was a French astronomer. He joined the Marseille Observatory in 1864. In the course of his career, he discovered a number of asteroids and comets, including the periodic c ...

on April 10, 1872, and independently by German-American astronomer

Christian Heinrich Friedrich Peters Christian Heinrich Friedrich Peters (September 19, 1813 – July 18, 1890) was a German–American university teacher and astronomer at the Litchfield Observatory of Hamilton College, New York, and a pioneer in the study and visual discovery of ...

on April 11, 1872, then named after

Lachesis Lachesis ( ; grc, Λάχεσις, Lákhesis, disposer of lots; from , 'to obtain by lot, by fate, or by the will of the gods'), in ancient Greek religion, was the second of the Three Fates, or Moirai; the others were her sisters, Clotho and A ...

, one of the

Moirai In ancient Greek religion and mythology, the Moirai (, also spelled Moirae or Mœræ; grc, Μοῖραι, "lots, destinies, apportioners"), often known in English as the Fates ( la, Fata, Fata, -orum (n)=), were the personifications of fate ...

, or Fates, in

Greek mythology A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical co ...

. A Lachesean

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 ...

of a star occurred in 1999 and was confirmed visually by five observers and once photoelectrically, with the chords yielding an estimated elliptical cross-section of . This body 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 Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

of 5.50 years and an

eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-center, in geometry * Eccentricity (graph theory) of a v ...

(ovalness) of 0.05. The

orbital plane The orbital plane of a revolving body is the geometric plane in which its orbit lies. Three non-collinear points in space suffice to determine an orbital plane. A common example would be the positions of the centers of a massive body (host) an ...

inclined Incline, inclined, inclining, or inclination may refer to: *Grade (slope), the tilt, steepness, or angle from horizontal of a topographic feature (hillside, meadow, etc.) or constructed element (road, railway, field, etc.) *Slope, the tilt, steepn ...

by 7° to the

plane of the ecliptic The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic agains ...

. Photometric observations of this asteroid were made in early 2009 at the Organ Mesa Observatory in

Las Cruces, New Mexico Las Cruces (; "the crosses") is the second-largest city in the U.S. state of New Mexico and the seat of Doña Ana County. As of the 2020 census the population was 111,385. Las Cruces is the largest city in both Doña Ana County and southern New ...

. The resulting

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 ...

shows a synodic

rotation period The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) may refer to its sidereal rotation period, i.e. the time that the object takes to complete a single revolution around its axis of rotation relative to the ...

of 46.551 ± 0.002 hours with a brightness variation of 0.14 ± 0.02 in

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

. It is a very slow rotator with the longest

of an asteroid more than 150 km in diameter. As a primitive

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 ...

it is probably composed of

carbonaceous Carbon () is a chemical element with the chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—its atom making four electrons available to form covalent bond, covalent chemical bonds. It belongs to gro ...

material.

References

External links

* * 000120 Discoveries by Alphonse Borrelly Named minor planets 000120 000120 18720410 {{C-beltasteroid-stub