11395 Iphinous, ''provisional designation'': , is a large Jupiter trojan from the Greek camp approximately in diameter. It was discovered on 15 December 1998, by astronomers with the

Lincoln Near-Earth Asteroid Research The Lincoln Near-Earth Asteroid Research (LINEAR) project is a collaboration of the United States Air Force, NASA, and the Massachusetts Institute of Technology's Lincoln Laboratory for the systematic detection and tracking of near-Earth objects ...

at the Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico, in the United States. The dark asteroid has a rotation period of 17.4 hours and possibly a spherical shape. The body is one of the 50 largest Jupiter trojans. It was named from Greek mythology after the Achaean soldier

Iphinous In Greek mythology, Iphinous (Ancient Greek: Ἰφίνοον) may refer to the following personages: * Iphinous, one of the centaurs who fought against the Lapiths at Pirithous' wedding. He was slain with a sword by Peleus during the said battle. ...

who was killed by

Glaucus In Greek mythology, Glaucus (; grc, Γλαῦκος, Glaûkos, glimmering) was a Greek prophetic sea-god, born mortal and turned immortal upon eating a magical herb. It was believed that he came to the rescue of sailors and fishermen in storms ...

in 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 ...

Orbit and classification

''Iphinous'' is a Jovian asteroid orbiting in the leading Greek camp at Jupiter's Lagrangian point, 60 ° ahead of the Gas Giant's orbit in a 1:1 resonance ''(see

Trojans in astronomy In astronomy, a trojan is a small celestial body (mostly asteroids) that shares the orbit of a larger body, remaining in a stable orbit approximately 60° ahead of or behind the main body near one of its Lagrangian points and . Trojans can shar ...

)''. 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 in the Jovian background population. The asteroid orbits the Sun at a distance of 4.9–5.6 AU once every 11 years and 11 months (4,345 days; semi-major axis of 5.21 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 0.07 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 24 ° 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 Siding Spring Observatory in February 1991, nearly 8 years prior to its official discovery observation at Socorro.

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 numbered on 31 August 1999 (). On 14 May 2021, the object was named by the

Working Group Small Body Nomenclature In ancient times, only the Sun and Moon, a few stars, and the most easily visible planets had names. Over the last few hundred years, the number of identified astronomical objects has risen from hundreds to over a billion, and more are discovered e ...

(WGSBN) after

from Greek mythology. An Achaean soldier who participated in the

, Iphinous was killed by

in hand-to-hand combat during the siege of Troy.

Physical characteristics

''Iphinous'' is a generically assumed

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 ...

. Many if not most Jupiter trojans show an even darker D or P-type spectrum.

Rotation period

In 2009 and 2010, two fragmentary

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 ...

s of ''Iphinous'' were obtained from photometric observations 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 Calar Alto Observatory in Spain. Lightcurve analysis gave a tentative rotation period of 13.696 and 13.70 hours with a brightness variation of 0.14 and 0.06

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 ...

, respectively (). During 2015–2017, three additional photometric observation were made at the Californian Center for Solar System Studies 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 ...

, Daniel Coley and Brian Warner in collaboration with Linda French from

Illinois Wesleyan University Illinois ( ) is a state in the Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolitan areas include, Peoria and Rockford ...

. The two best-rated lightcurves gave a period of 17.383 and 17.44 with an amplitude of 0.08 and 0.11 magnitude, respectively, indicating that the body has a nearly spherical shape ().

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite, 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

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 ...

, ''Iphinous'' measures between 64.71 and 68.98 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 0.045 and 0.067. The ''Collaborative Asteroid Lightcurve Link'' derives an albedo of 0.0510 and a diameter of 64.51 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 9.8.

Notes

References

External links

Asteroid Lightcurve Database (LCDB)
query form

)

– Minor Planet Center * * {{DEFAULTSORT:Iphinous 011395 011395 011395 Minor planets named from Greek mythology Named minor planets 19981215