4791 Iphidamas is a

Jupiter trojan The Jupiter trojans, commonly called trojan asteroids or simply trojans, are a large group of asteroids that share the planet Jupiter's orbit around the Sun. Relative to Jupiter, each trojan librates around one of Jupiter's stable Lagrange p ...

from the

Trojan camp This is a list of Jupiter trojans that lie in the Trojan camp, an elongated curved region around the trailing Lagrangian point, 60° behind Jupiter. All the asteroids at the trailing point have names corresponding to participants on the Trojan ...

, approximately in diameter. It was discovered on 14 August 1988, by American astronomer

Carolyn Shoemaker Carolyn Jean Spellmann Shoemaker (June 24, 1929 – August 13, 2021) was an American astronomer and a co-discoverer of Comet Shoemaker–Levy 9. She discovered 32 comets (then a record for the most by an individual) and more than 500 astero ...

at the

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. The dark Jovian

asteroid An asteroid is a minor planet of the Solar System#Inner solar system, 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 o ...

belongs the 100 largest Jupiter trojans and has 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 9.7 hours. It was named after the Trojan warrior

Iphidamas In Greek mythology, the name Iphidamas (Ancient Greek: Ἰφιδάμας, gen. Ἰφιδάμαντος) may refer to: * Iphidamas, also known as Amphidamas, son of Aleus and counted as one of the Argonauts. * Iphidamas (or Amphidamas), a son of B ...

, from Greek mythology.

Orbit and classification

''Iphidamas'' is a dark

in a 1:1

orbital resonance In celestial mechanics, orbital resonance occurs when orbiting bodies exert regular, periodic gravitational influence on each other, usually because their orbital periods are related by a ratio of small integers. Most commonly, this relations ...

with Jupiter. It is located in the trailering

at the Gas Giant's

Lagrangian point In celestial mechanics, the Lagrange points (; also Lagrangian points or libration points) are points of equilibrium for small-mass objects under the influence of two massive orbiting bodies. Mathematically, this involves the solution of ...

, 60 ° behind its orbit . It is also 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 of the Jovian background population. It orbits the Sun at a distance of 4.9–5.4 AU once every 11 years and 9 months (4,281 days;

semi-major axis In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the lo ...

of 5.16 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- center, in geometry * Eccentricity (graph theory) of a ...

of 0.05 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 26 ° 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 agai ...

. 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 its official discovery observation at Palomar in August 1988.

Physical characteristics

''Iphidamas'' is an assumed, carbonaceous

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 has a high V–I color index of 1.03 ''(see table below)''.

Rotation period

In 2014 and 2015, 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 ''Iphidamas'' were obtained from photometric observations by

Robert Stephens Sir Robert Graham Stephens (14 July 193112 November 1995) was a leading English actor in the early years of Britain's Royal National Theatre. He was one of the most respected actors of his generation and was at one time regarded as the natu ...

at the

Center for Solar System Studies This is a list of observatory codes (IAU codes or MPC codes) published by the Minor Planet Center. For a detailed description, ''see observations of small Solar System bodies''. List References * {{DEFAULTSORT:Observat ...

in Landers, California. Analysis of the best-rated lightcurve from December 2015 showed a

of hours with a brightness amplitude of 0.31

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 ...

(), superseding a previous period determination by

Stefano Mottola This is a list of minor-planet discoverers credited by the Minor Planet Center with the discovery of one or several minor planets (such as near-Earth and main-belt asteroids, Jupiter trojans and distant objects). , the discovery of 612,011 numb ...

at the

La Silla Observatory La Silla Observatory is an 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 observatory is ...

from February 1992, which gave a similar period of 9.57 hours ().

Diameter and albedo

According to the surveys 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 20 ...

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 2 ...

, the Infrared Astronomical Satellite

IRAS The Infrared Astronomical Satellite ( Dutch: ''Infrarood Astronomische Satelliet'') (IRAS) was the first space telescope to perform a survey of the entire night sky at infrared wavelengths. Launched on 25 January 1983, its mission lasted ten mo ...

, and the Japanese Akari satellite, ''Iphidamas'' measures between 49.528 and 59.96 kilometers in diameter and its surface has an

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 0.055 and 0.079. The ''Collaborative Asteroid Lightcurve Link'' derives an albedo of 0.0483 and a diameter of 57.74 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 we ...

of 10.1.

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 '' ...

was named from

Greek mythology A major branch of classical mythology, Greek mythology is the body of myths originally told by the ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the origin and nature of the world, the lives and activities of ...

after the Trojan warrior

, son of

Theano In Greek mythology, Theano (; Ancient Greek: Θεανώ) may refer to the following personages: *Theano, wife of Metapontus, king of Icaria. Metapontus demanded that she bear him children, or leave the kingdom. She presented the children of Mela ...

and

Antenor __NOTOC__ Antenor ( grc-gre, Ἀντήνωρ, ''Antḗnōr''; BC) was an Athenian sculptor. He is recorded as the creator of the joint statues of the tyrannicides Harmodius and Aristogeiton funded by the Athenians on the expulsion of Hipp ...

, who was the counselor of King

Priam In Greek mythology, Priam (; grc-gre, Πρίαμος, ) was the legendary and last king of Troy during the Trojan War. He was the son of Laomedon. His many children included notable characters such as Hector, Paris, and Cassandra. Etymology ...

. During the

Trojan War In Greek mythology, the Trojan War was waged against the city of Troy by the Achaeans (Greeks) after Paris of Troy took Helen from her husband Menelaus, king of Sparta. The war is one of the most important events in Greek mythology and ha ...

, he confronted

Agamemnon In Greek mythology, Agamemnon (; grc-gre, Ἀγαμέμνων ''Agamémnōn'') was a king of Mycenae who commanded the Greeks during the Trojan War. He was the son, or grandson, of King Atreus and Queen Aerope, the brother of Menelaus, the husb ...

in battle, but his spear bent against Agamemnon's war belt, who then killed Iphidamas with his sword. The official 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 27 June 1991 ().

Orbit and classification

Physical characteristics

Rotation period

Diameter and albedo

Naming

Notes

References

External links