163 Erigone is an

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. ...

from the

asteroid 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 ...

and the namesake of the

Erigone family An asteroid family is a population of asteroids that share similar proper orbital elements, such as semimajor axis, eccentricity, and orbital inclination. The members of the families are thought to be fragments of past asteroid collisions. An ...

of asteroids that share similar

orbital elements Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit. There are many different ways to mathematically describe the same ...

and properties. It was discovered by French astronomer

Henri Joseph Perrotin Henri Joseph Anastase Perrotin (December 19, 1845 – February 29, 1904) was a French astronomer and a discoverer of minor planets. Some sources give his middle name as Athanase. In his early career, he and Guillaume Bigourdan were assis ...

on April 26, 1876, and named after one of the two Erigones 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 ...

. This asteroid 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 ...

at a distance of 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 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 0.19. 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 ...

is inclined at an angle of 4.8° 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 measurements taken in 2014 were used to construct a

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 ...

that demonstrated a

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 with an

amplitude The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of amplit ...

of in magnitude. Erigone is a relatively large and dark asteroid with an estimated size of 73 km. Based upon its spectrum, it is classified 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 ...

, which indicates that it probably has a carbonaceous composition. It is the largest member of the eponymously named Erigone collisional family.

2014 occultation of Regulus

Outline map of the path of the shadow of asteroid (163) Erigone as it occults Regulus on March 20, 2014

In the early morning hours of March 20, 2014, Erigone occulted the first-magnitude star

Regulus Regulus is the brightest object in the constellation Leo and one of the brightest stars in the night sky. It has the Bayer designation designated α Leonis, which is Latinized to Alpha Leonis, and abbreviated Alpha Leo or α Leo. Re ...

, as first predicted by Aldo Vitagliano in 2004 using the

SOLEX Solex may refer to: * Solex (musician), Dutch musician * Solex Carburetor, a French manufacturer of carburetors and the powered bicycle VéloSoleX * Solex College, a former private for-profit college in Chicago, Illinois * Solex Unit, a fictiona ...

software. This would have been a rare case of an occultation of a very bright star visible from a highly populated area, since the shadow path moved across

New York state New York, officially the State of New York, is a state in the Northeastern United States. It is often called New York State to distinguish it from its largest city, New York City. With a total area of , New York is the 27th-largest U.S. stat ...

and

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...

, including all five boroughs of

New York City New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...

. Observers in the shadow path would have seen the star wink out for as long as 14 seconds. However, heavy clouds and rain blocked the view for most if not all people on the shadow path. The website of the

International Occultation Timing Association International is an adjective (also used as a noun) meaning "between nations". International may also refer to: Music Albums * ''International'' (Kevin Michael album), 2011 * ''International'' (New Order album), 2002 * ''International'' (The T ...

does not list any successful observations at all. Two single chord

Asteroid 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 ...

events have been observed, in 2013 and 2015.

References

External links

* * {{DEFAULTSORT:000163 Erigone asteroids Erigone Erigone C-type asteroids (Tholen) Ch-type asteroids (SMASS) 20140320 18760426 Objects observed by stellar occultation vec:Lista de asteroidi#163 Erigona