5143 Heracles, provisional designation , is a highly eccentric, rare-type
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.
...
and synchronous
binary system, classified as
near-Earth object
A near-Earth object (NEO) is any small Solar System body whose orbit brings it into proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). ...
of the
Apollo group
Apollo Education Group, Inc. is an American corporation based in the South Phoenix area of Phoenix, Arizona, with an additional corporate office in Chicago, Illinois.
The company owns and operates several higher-learning institutions, including ...
, approximately 4.8 kilometers in diameter. The asteroid was discovered on 7 November 1991, by American astronomer
Carolyn Shoemaker at
Palomar Observatory
Palomar Observatory is an astronomical research observatory in San Diego County, California, United States, in the Palomar Mountain Range. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observat ...
in California, United States.
It is named for the Greek divine hero
Heracles
Heracles ( ; grc-gre, Ἡρακλῆς, , glory/fame of Hera), born Alcaeus (, ''Alkaios'') or Alcides (, ''Alkeidēs''), was a divine hero in Greek mythology, the son of Zeus and Alcmene, and the foster son of Amphitryon.By his adoptive ...
.
It has an Earth
minimum orbit intersection distance of and is associated with the
Beta Taurids daytime meteor shower.
[
]
Classification and orbit
''Heracles'' orbits the Sun in the inner
Interior may refer to:
Arts and media
* ''Interior'' (Degas) (also known as ''The Rape''), painting by Edgar Degas
* ''Interior'' (play), 1895 play by Belgian playwright Maurice Maeterlinck
* ''The Interior'' (novel), by Lisa See
* Interior de ...
main-belt at a distance of 0.4–3.2 AU once every 2 years and 6 months (907 days). Its orbit has an eccentricity of 0.77 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 9 ° with respect to the ecliptic. The first precovery
In astronomy, precovery (short for pre-discovery recovery) is the process of finding the image of an object in images or photographic plates predating its discovery, typically for the purpose of calculating a more accurate orbit. This happens mos ...
was taken at Palomar during the ''Digitized Sky Survey
The Digitized Sky Survey (DSS) is a digitized version of several photographic astronomical surveys of the night sky, produced by the Space Telescope Science Institute between 1983 and 2006.
Versions and source material
The term Digitized Sky S ...
'' in 1953, extending 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 ...
by 38 years prior to its official discovery observation.
Due to its high eccentricity, ''Heracles'' is also a Mercury-grazer and a Mars-crosser. It has an ''Earth minimum orbital intersection distance'' of which corresponds to 22.8 lunar distances.
Physical characteristics
Spectral type
In the SMASS taxonomy, ''Heracles'' is a rare O-type asteroid The rare O-type asteroids have spectra similar to the unusual asteroid 3628 Boznemcová, which is the best asteroid match to the spectra of L6 and LL6 ordinary chondrite meteorites. Their spectra have a deep absorption feature longward of 0.75 μm ...
, which have spectra similar to those of stony chondritic meteorites of the L6 and LL6 type. However, it has also been characterized as a carbonaceous C-type, as well as a stony Sk and Q-type asteroid
Q-type asteroids are relatively uncommon inner-belt asteroids with a strong, broad 1 micrometre olivine and pyroxene feature, and a spectral slope that indicates the presence of metal. There are absorption features shortwards and longwards of 0. ...
.
Lightcurves
A large number of rotational lightcurves of ''Heracles'' were obtained from photometric observations between 2006 and 2016. Best rated lightcurves gave 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 ...
between 2.7051 and 2.7065 hours with a brightness variation of 0.05 to 0.20 magnitude ().
Diameters
According to the surveys carried out by the Spitzer Space Telescope
The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003. Operations ended on 30 January 2020. Spitzer was the third space telescope dedicated to infrared astronomy, f ...
, the Japanese Akari satellite, and 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 2011, ...
with its subsequent NEOWISE mission, the asteroid measures between 3.26 and 4.843 kilometers 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 ...
between 0.20 and 0.24. The ''Collaborative Asteroid Lightcurve Link'' adopts the results from Petr Pravec
Petr Pravec (born September 17, 1967) is a Czech astronomer and a discoverer of minor planets, born in Třinec, Czech Republic.
Pravec is a prolific discoverer of binary asteroids, expert in photometric observations and rotational lightcurves a ...
's revised WISE data, that is, an albedo of 0.1481 and a diameter of 4.83 kilometers with an 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 ...
of 14.27.
Binary system
On 12 July 2012, it was announced that ''Heracles'' is an assumed synchronous binary asteroid with a minor-planet moon orbiting its primary in a retrograde motion
Retrograde motion in astronomy is, in general, orbital or rotational motion of an object in the direction opposite the rotation of its primary, that is, the central object (right figure). It may also describe other motions such as precession or ...
approximately every 16 hours. The companion was discovered in December 2011, by a team of astronomers using radar observations from Arecibo Observatory
The Arecibo Observatory, also known as the National Astronomy and Ionosphere Center (NAIC) and formerly known as the Arecibo Ionosphere Observatory, is an observatory in Barrio Esperanza, Arecibo, Puerto Rico owned by the US National Science F ...
in Puerto Rico, following months of intensive photometric lightcurve observations ''(see above)''. It was designated .
A longer orbital period
The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...
of 40–57 hours cannot be excluded, which would then no-longer be a synchronous system. Estimated diameters for ''Heracles'' and its moon are and kilometer, respectively.
Follow-up observations in 2016 confirmed an orbital period of 17 hours for the asteroid moon.
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 after Heracles
Heracles ( ; grc-gre, Ἡρακλῆς, , glory/fame of Hera), born Alcaeus (, ''Alkaios'') or Alcides (, ''Alkeidēs''), was a divine hero in Greek mythology, the son of Zeus and Alcmene, and the foster son of Amphitryon.By his adoptive ...
, the divine gatekeeper of the Olympus
Olympus or Olympos ( grc, Ὄλυμπος, link=no) may refer to:
Mountains
In antiquity
Greece
* Mount Olympus in Thessaly, northern Greece, the home of the twelve gods of Olympus in Greek mythology
* Mount Olympus (Lesvos), located in Les ...
and one of the greatest heroes 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 ...
, known for his strength and his '' Twelve Labors''. Heracles is the son of Zeus and Alcmena, after whom the asteroids and were named. In the Roman adaptation, Heracles is known as Hercules
Hercules (, ) is the Roman equivalent of the Greek divine hero Heracles, son of Jupiter and the mortal Alcmena. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures.
The Romans adapted the Gr ...
. 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 14 July 1992 ().
Notes
References
External links
(5143) Heracles at johnstonsarchive
datasheet, Robert Johnston
Robert Johnston, johnstonsarchive.net
Asteroid Lightcurve Database (LCDB)
query form
)
Dictionary of Minor Planet Names
Google books
– Observatoire de Genève, Raoul Behrend
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005143
Discoveries by Carolyn S. Shoemaker
Named minor planets
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