4000 Hipparchus is a dark background
asteroid from the central regions 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, c ...
, approximately in diameter. It was discovered on 4 January 1989, by Japanese astronomers
Seiji Ueda and
Hiroshi Kaneda
is a Japanese astronomer and discoverer of minor planets from Sapporo, in the northernmost prefecture of Japan.
Kaneda ranks among the world's most prolific individual discoverers of minor planets. He is credited by the Minor Planet Center with ...
at the
Kushiro Observatory on Hokkaido, Japan.
The likely
carbonaceous asteroid has a short
rotation period of 3.4 hours.
It was named for the ancient Greek astronomer
Hipparchus
Hipparchus (; el, Ἵππαρχος, ''Hipparkhos''; BC) was a Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidental discovery of the precession of the equi ...
.
Orbit and classification
''Hipparchus'' is a non-
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
asteroid from the main belt's
background population (according to Nesvorný).
Conversely, an alternative application of the
hierarchical clustering method
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 ...
found it to be a core member of the
Astraea family (according to Milani and Knežević).
It orbits the Sun in the
central asteroid belt at a distance of 2.3–2.9
AU once every 4 years and 2 months (1,523 days;
semi-major axis of 2.59 AU). 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 0.11 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 reference plane and the orbital plane or axis of direction of the orbiting object.
For a satellite orbiting the Eart ...
of 3
° 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 agains ...
.
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 with a
precovery taken at the
Palomar Observatory in November 1954, or more than 34 years prior to its official discovery observation at Kushiro .
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 ''mino ...
was named by IAU's
Working Group for Planetary System Nomenclature
The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach ...
after the Greek astronomer
Hipparchus
Hipparchus (; el, Ἵππαρχος, ''Hipparkhos''; BC) was a Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidental discovery of the precession of the equi ...
( BC), considered to be the greatest astronomer of ancient times. Hipparchus introduced a systematic and critical approach to both theoretical and observational astronomy. He is also honored by a lunar and a Martian crater (''
Hipparchus
Hipparchus (; el, Ἵππαρχος, ''Hipparkhos''; BC) was a Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidental discovery of the precession of the equi ...
'' and ''
Hipparchus
Hipparchus (; el, Ἵππαρχος, ''Hipparkhos''; BC) was a Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidental discovery of the precession of the equi ...
'', respectively).
The official naming citation was published by the
Minor Planet Center on 21 November 1991 ().
The asteroid is one of several early "kilo-numbered" minor planets that were dedicated to renowned scientists or institutions including:
*
1000 Piazzia named for
Giuseppe Piazzi
Giuseppe Piazzi ( , ; 16 July 1746 – 22 July 1826) was an Italian Catholic priest of the Theatine order, mathematician, and astronomer. He established an observatory at Palermo, now the '' Osservatorio Astronomico di Palermo – Giuseppe S ...
, discoverer of
Ceres
Ceres most commonly refers to:
* Ceres (dwarf planet), the largest asteroid
* Ceres (mythology), the Roman goddess of agriculture
Ceres may also refer to:
Places
Brazil
* Ceres, Goiás, Brazil
* Ceres Microregion, in north-central Goiás ...
*
2000 Herschel for
William Herschel
Frederick William Herschel (; german: Friedrich Wilhelm Herschel; 15 November 1738 – 25 August 1822) was a German-born British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline ...
who discovered
Uranus
Uranus is the seventh planet from the Sun. Its name is a reference to the Greek god of the sky, Uranus ( Caelus), who, according to Greek mythology, was the great-grandfather of Ares (Mars), grandfather of Zeus (Jupiter) and father of ...
*
3000 Leonardo for the Italian polymath of the Renaissance,
Leonardo da Vinci
Leonardo di ser Piero da Vinci (15 April 14522 May 1519) was an Italian polymath of the High Renaissance who was active as a painter, Drawing, draughtsman, engineer, scientist, theorist, sculptor, and architect. While his fame initially res ...
4000 Hipparchus is follow by the asteroids
5000 IAU (for the
International Astronomical Union
The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...
),
6000 United Nations (for the
United Nations
The United Nations (UN) is an intergovernmental organization whose stated purposes are to maintain international peace and security, develop friendly relations among nations, achieve international cooperation, and be a centre for harmoniz ...
),
7000 Curie (for the pioneers on radioactivity,
Marie
Marie may refer to:
People Name
* Marie (given name)
* Marie (Japanese given name)
* Marie (murder victim), girl who was killed in Florida after being pushed in front of a moving vehicle in 1973
* Marie (died 1759), an enslaved Cree person in Tr ...
and
Pierre Curie
Pierre Curie ( , ; 15 May 1859 – 19 April 1906) was a French physicist, a pioneer in crystallography, magnetism, piezoelectricity, and radioactivity. In 1903, he received the Nobel Prize in Physics with his wife, Marie Curie, and Henri Becq ...
), and (for
Isaac Newton
Sir Isaac Newton (25 December 1642 – 20 March 1726/27) was an English mathematician, physicist, astronomer, alchemist, theologian, and author (described in his time as a " natural philosopher"), widely recognised as one of the grea ...
),
while
9000 Hal (after
HAL 9000
HAL 9000 is a fictional artificial intelligence character and the main antagonist in Arthur C. Clarke's ''Space Odyssey'' series. First appearing in the 1968 film '' 2001: A Space Odyssey'', HAL ( Heuristically programmed ALgorithmic computer) ...
from the movie ''
2001: A Space Odyssey'') and
10000 Myriostos (after the Greek word for ten-thousandth, and to honor all astronomers) were named based on their direct numeric accordance.
Physical characteristics
Based on its low albedo of around 0.04–0.05 ''(see below)'', ''Hipparchus'' is likely of a carbonaceous rather than siliceous composition, among which the
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 ...
are the most common ones in the asteroid belt.
Rotation period
In February 2014, a 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 freq ...
of ''Hipparchus'' was obtained from
photometric observations by astronomers at the Phillips Academy and HUT observatories. Lightcurve analysis gave a
rotation period of hours with a brightness amplitude of 0.11
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 ...
().
A previous observation at the
Palomar Transient Factory from August 2012, only gave a fragmentary lightcurve with a longer period of 7.935 hours ().
Diameter and albedo
According to the surveys carried out by the Japanese
Akari satellite and 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 201 ...
mission of NASA's
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 201 ...
, ''Hipparchus'' measures between 15.13 and 18.87 kilometers in diameter and its surface has a low
albedo
Albedo (; ) is the measure of the diffuse reflection of 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 that refl ...
between 0.039 and 0.052.
The ''Collaborative Asteroid Lightcurve Link'' assumes a standard albedo for a stony asteroid (rather than for a carbonaceous one) and consequently and calculates a smaller diameter of 8.18 kilometers based on an
absolute magnitude
Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse logarithmic astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it ...
of 12.8.
References
External links
Asteroid 4000 Hipparchus Small Bodies Data Ferret
Asteroid Lightcurve Database (LCDB) query form
)
Dictionary of Minor Planet Names Google books
– Minor Planet Center
*
*
{{DEFAULTSORT:Hipparchus
004000
Discoveries by Seiji Ueda
Discoveries by Hiroshi Kaneda
Named minor planets
19890104