9694 Lycomedes is a Jupiter trojan from the Greek camp, approximately in diameter. It was discovered during the

Palomar–Leiden survey The Palomar–Leiden survey (PLS) was a successful astronomical survey to study faint minor planets in a collaboration between the U.S Palomar Observatory and the Dutch Leiden Observatory, and resulted in the discovery of thousands of asteroids, ...

at the Palomar Observatory in 1960 and later named after

Lycomedes In Greek mythology, Lycomedes ( grc, Λυκομήδης), also known as Lycurgus, was the most prominent king of the Dolopians in the island of Scyros near Euboea during the Trojan War. Family Lycomedes was the father of seven daughters inc ...

from Greek mythology. The dark Jovian asteroid is likely elongated in shape and has a rotation period of 18.2 hours.

Discovery

''Lycomedes'' was discovered on 26 September 1960, by Dutch astronomer couple

Ingrid Ingrid may refer to: * Ingrid (given name) * Ingrid (record label), and artist collective * Ingrid Burley, rapper known mononymously as Ingrid * Tropical Storm Ingrid, various cyclones * 1026 Ingrid, an asteroid * InGrid, the grid computing project ...

and

Cornelis van Houten Cornelis Johannes van Houten (18 February 1920 – 24 August 2002) was a Dutch astronomer, sometimes referred to as Kees van Houten. Early life and education Born in The Hague, he spent his entire career at Leiden University except for a brief p ...

at Leiden, on photographic plates taken by astronomer

Tom Gehrels Anton M.J. "Tom" Gehrels (February 21, 1925 – July 11, 2011) was a Dutch–American astronomer, Professor of Planetary Sciences, and Astronomer at the University of Arizona, Tucson. Biography Youth and education Gehrels was born at Haa ...

at the Palomar Observatory in California. 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 the night after its official discovery observation at Palomar.

Palomar–Leiden survey

The survey designation "P-L" stands for "Palomar–Leiden", named after Palomar and Leiden observatories, which collaborated on the fruitful

in the 1960s. Gehrels used Palomar's

Samuel Oschin telescope The Samuel Oschin telescope, also called the Oschin Schmidt, is a Schmidt camera at the Palomar Observatory in northern San Diego County, California. It consists of a 49.75-inch Schmidt corrector plate and a 72-inch (f/2.5) mirror. The instrument ...

(also known as the 48-inch Schmidt Telescope), and shipped the photographic plates to Ingrid and Cornelis van Houten at Leiden Observatory where astrometry was carried out. The trio are credited with the discovery of several thousand asteroids.

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 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 ...

after

, the Greek king of

Scyros Skyros ( el, Σκύρος, ), in some historical contexts Latinized Scyros ( grc, Σκῦρος, ), is an island in Greece, the southernmost of the Sporades, an archipelago in the Aegean Sea. Around the 2nd millennium BC and slightly later, the ...

. At the request of

Thetis Thetis (; grc-gre, Θέτις ), is a figure from Greek mythology with varying mythological roles. She mainly appears as a sea nymph, a goddess of water, or one of the 50 Nereids, daughters of the ancient sea god Nereus. When described as ...

, he concealed her son

Achilles In Greek mythology, Achilles ( ) or Achilleus ( grc-gre, Ἀχιλλεύς) was a hero of the Trojan War, the greatest of all the Greek warriors, and the central character of Homer's '' Iliad''. He was the son of the Nereid Thetis and Pele ...

dressed in girl's clothes among his own daughters to save him from 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 ...

until Odysseus drew him out of his disguise. The official naming citation was published by the Minor Planet Center on 2 April 1999 ().

Orbit and classification

As all Jupiter trojans, ''Lycomedes'' is 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 relationsh ...

with

Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...

. It is located in the leading Greek camp at the Gas Giant's Lagrangian point, 60 ° ahead on its orbit . It orbits the Sun at a distance of 4.9–5.3 AU once every 11 years and 6 months (4,206 days; semi-major axis of 5.1 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 0.04 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 5 ° 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 ...

Physical characteristics

''Lycomedes'' is an 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 ...

, while most larger Jupiter trojans are D-types.

Rotation period

In October 2010, a first 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 ''Lycomedes'' was obtained from photometric observations by astronomers at the Palomar Transient Factory in California. Lightcurve analysis gave a rotation period of hours with a brightness amplitude of 0.38

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 ...

(). In November 2011, follow-up observations over two consecutive nights were made by Daniel Coley at the Goat Mountain Astronomical Research Station in California. It gave a concurring rotation period of hours with a high brightness amplitude of 0.55

, indicative of a non-spherical shape ().

Diameter and albedo

According to the survey 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 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 ...

, ''Lycomedes'' measures between 31.736 and 31.74 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 ...

, while the ''Collaborative Asteroid Lightcurve Link'' assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 40.33 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 10.7.

Notes

References

External links

Lightcurve Database Query
(LCDB), at ''www.minorplanet.info''
Dictionary of Minor Planet Names
Google books

– Minor Planet Center
Asteroid 9694 Lycomedes
at the Small Bodies Data Ferret * * {{DEFAULTSORT:Lycomedes 009694 Discoveries by Cornelis Johannes van Houten Discoveries by Ingrid van Houten-Groeneveld Discoveries by Tom Gehrels 6581 Named minor planets 19600926