24101 Cassini, provisional designation ', is an eccentric background
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 middle region of 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 ...
, approximately 7 kilometers in diameter. It was discovered on 9 November 1999, by American amateur astronomer
Charles Juels at the Fountain Hills Observatory in Arizona, United States.
It was named after Italian–French astronomer
Giovanni Cassini
Giovanni Domenico Cassini, also known as Jean-Dominique Cassini (8 June 1625 – 14 September 1712) was an Italian (naturalised French) mathematician, astronomer and engineer. Cassini was born in Perinaldo, near Imperia, at that time in the C ...
.
Orbit and classification
''Cassini'' is a non-
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
from the main belt's
background population. It orbits the Sun in the
central
Central is an adjective usually referring to being in the center of some place or (mathematical) object.
Central may also refer to:
Directions and generalised locations
* Central Africa, a region in the centre of Africa continent, also known as ...
asteroid belt at a distance of 1.8–3.5
AU once every 4 years and 4 months (1,571 days). Its orbit has 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-Centre (geometry), center, in geometry
* Eccentricity (g ...
of 0.31 and an
inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...
of 15
° with respect to 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 again ...
.
In December 1926, the asteroid was first identified as ' at
Heidelberg Observatory
Heidelberg (; Palatine German: ') is a city in the German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. As of the 2016 census, its population was 159,914, of which roughly a quarter consisted of student ...
in Germany. The body's
observation arc
In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...
begins 7 years prior to its official discovery observation, with a
precovery taken at
La Silla Observatory
La Silla Observatory is an astronomy, astronomical observatory in Chile with three telescopes built and operated by the European Southern Observatory (ESO). Several other telescopes are located at the site and are partly maintained by ESO. The obse ...
in March 1992.
Physical characteristics
Lightcurve
In February 2009, two rotational
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 ...
s of ''Cassini'' were obtained from photometric observations by Italian astronomer
Silvano Casulli
__NOTOC__
Vincenzo Silvano Casulli, usually known as Silvano Casulli (25 August 1944 – 24 July 2018 , and at the private Shed of Science Observatory () in Minnesota, United States. Lightcurve analysis gave a well-defined, concurring
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 hours with a brightness variation of 0.12
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 ...
().
Diameter and albedo
According to observations carried out by the
NEOWISE
Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and SMEX-6) is a NASA infrared astronomy space telescope in the Explorers Program. It was launched in December 2009, and placed in hibernation mode in February 2011, ...
mission of NASA's space-based
Wide-field Infrared Survey Explorer
Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and SMEX-6) is a NASA infrared astronomy space telescope in the Explorers Program. It was launched in December 2009, and placed in hibernation mode in February 2011, ...
, ''Cassini'' measures 7.051 kilometer in diameter and its surface has an
albedo
Albedo (; ) is the measure of the diffuse reflection of sunlight, solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body ...
of 0.2458.
The ''Collaborative Asteroid Lightcurve Link'' assumes an albedo of 0.10 – a compromise value between the brighter
stony (0.20) and darker
carbonaceous
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes up ...
(0.057) asteroids of the 2.6 to 2.7 AU-region of the asteroid belt – and correspondingly, calculates a larger diameter of 11.05 kilometers, as the lower a body's albedo (reflectivity), the larger its diameter for a given
absolute magnitude
Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent mag ...
(brightness).
Naming
This
minor planet
According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...
was named in honor of Italian-born French astronomer
Giovanni Cassini
Giovanni Domenico Cassini, also known as Jean-Dominique Cassini (8 June 1625 – 14 September 1712) was an Italian (naturalised French) mathematician, astronomer and engineer. Cassini was born in Perinaldo, near Imperia, at that time in the C ...
(1625–1712), who was the first director of the
Paris Observatory
The Paris Observatory (french: Observatoire de Paris ), a research institution of the Paris Sciences et Lettres University, is the foremost astronomical observatory of France, and one of the largest astronomical centers in the world. Its histor ...
from 1671 until his death. He discovered the four
moons of Saturn
The moons of Saturn are numerous and diverse, ranging from tiny moonlets only tens of meters across to enormous Titan (moon), Titan, which is larger than the planet Mercury (planet), Mercury. Saturn has 83 natural satellite, moons with confirmed ...
–
Iapetus
In Greek mythology, Iapetus (; ; grc, Ἰαπετός, Iapetós), also Japetus, is a Titan, the son of Uranus and Gaia and father of Atlas, Prometheus, Epimetheus, and Menoetius. He was also called the father of Buphagus and Anchiale in other ...
,
Rhea,
Tethys and
Dione – the major gap in its rings, known as
Cassini Division, and was the first to write down observations of the
zodiacal light
The zodiacal light (also called false dawn when seen before sunrise) is a faint glow of diffuse sunlight scattered by interplanetary dust. Brighter around the Sun, it appears in a particularly dark night sky to extend from the Sun's direction in ...
. The
Cassini–Huygens
''Cassini–Huygens'' ( ), commonly called ''Cassini'', was a space research, space-research mission by NASA, the European Space Agency (ESA), and the Italian Space Agency (ASI) to send a space probe to study the planet Saturn and its system, i ...
spacecraft is named after him and
Christiaan Huygens
Christiaan Huygens, Lord of Zeelhem, ( , , ; also spelled Huyghens; la, Hugenius; 14 April 1629 – 8 July 1695) was a Dutch mathematician, physicist, engineer, astronomer, and inventor, who is regarded as one of the greatest scientists of ...
.
The
lunar
Lunar most commonly means "of or relating to the Moon".
Lunar may also refer to:
Arts and entertainment
* ''Lunar'' (series), a series of video games
* "Lunar" (song), by David Guetta
* "Lunar", a song by Priestess from the 2009 album ''Prior t ...
and
Martian
Mars, the fourth planet from the Sun, has appeared as a setting in works of fiction since at least the mid-1600s. It became the most popular celestial object in fiction in the late 1800s as the Moon was evidently lifeless. At the time, the pr ...
craters ''Cassini'' are also named in his honor. The approved naming citation was published by the
Minor Planet Center
The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory.
Function
...
on 21 September 2002 ().
References
References
External links
Asteroid Lightcurve Database (LCDB) query form
)
Dictionary of Minor Planet Names Google books
– Observatoire de Genève, Raoul Behrend
– Minor Planet Center
*
*
{{DEFAULTSORT:Cassini
024101
Discoveries by Charles W. Juels
Named minor planets
24101 Cassini
19991109