5261 Eureka was discovered at Mt Palomar on June 20, 1990 and turned out to be the first known Mars Trojan asteroid. It trails Mars (at the L₅ point) at a distance varying by only 0.3 AU during each revolution (with a secular trend superimposed, changing the distance from 1.5-1.8 AU around 1850 to 1.3-1.6 AU around 2400). Minimum distances from the Earth, Venus and Jupiter are 0.5, 0.8 and 3.5 AU, respectively. David H. Levy (born 1948) is a Canadian astronomer and science writer most famous for his co-discovery of Comet Shoemaker-Levy 9, which collided with the planet Jupiter in 1994. ... June 20 is the 171st day of the year (172nd in leap years) in the Gregorian Calendar, with 194 days remaining. ... 1990 is a common year starting on Monday of the Gregorian calendar. ... The provisional designation of comets and asteroids are similar to each other: they both follow a pattern set in 1925 by the Minor Planet Center of the IAU. Historical designations At first, astronomers strove to assign symbols to the minor planets: 1 Ceres a stylized sickle 2 Pallas a lozenge... Minor planets, or planetoids are minor bodies of the solar system orbiting the sun that are larger than meteoroids (the largest of which might be taken to be around 10 meters or so across) but smaller than major planets (Mercury having a diameter of about 4880 km). ... A Mars-crosser asteroid is an asteroid whose orbit crosses that of Mars. ... In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... July 14 is the 195th day (196th in leap years) of the year in the Gregorian Calendar, with 170 days remaining. ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... The Julian day or Julian day number (JDN) is the number of SI days that have elapsed since 12 noon Greenwich Mean Time (UT or TT) on Monday, January 1, 4713 BC in the proleptic Julian calendar 1. ... (This page refers to eccitricity in astrodynamics. ... In geometry, the semi-major axis (also semimajor axis) a applies to ellipses and hyperbolas. ... Giga (symbol: G) is a prefix in the SI system of units denoting 109, or 1 000 000 000. ... The metre is the basic unit of length in the International System of Units (SI: Système International dUnités). ... The astronomical unit (AU or au or a. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... A day is any of several different units of time. ... A Julian year is the length of an average year in the Julian calendar, 365. ... The orbital speed of a body, generally a planet, a natural satellite, an artificial satellite, or a multiple star, is the speed at which it orbits around the barycenter of a system, usually around a more massive body. ... The second (symbol s) is a unit for time, and one of seven SI base units. ... Inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit and is the angular distance of the orbital plane from the plane of the reference (usually planets equator or the ecliptic), stated in degrees. ... A degree (or in full a degree of arc), usually symbolized °, is a measurement of plane angle, representing 1/360 of a full rotation. ... The Longitude of the ascending node () is one of the orbital elements used to specify the orbit of an object in space. ... The argument of the perihelion is one of the orbital elements describing the orbit of a planet. ... In the study of orbital dynamics the mean anomaly is a measure of time, specific to the orbiting body p, which is a multiple of 2π radians at and only at periapsis. ... Mass is a property of physical objects that, roughly speaking, measures the amount of matter they contain. ... The international prototype, made of platinum-iridium, which is kept at the BIPM under conditions specified by the 1st CGPM in 1889. ... Density (symbol: ρ - Greek: rho) is a measure of mass per unit of volume. ... A cubic centimetre (cm3) is an SI derived unit of volume, equal to the volume of a cube with side length of 1 centi metre. ... It has been suggested that Law of universal gravitation be merged into this article or section. ... In physics, for a given gravitational field and a given position, the escape velocity is the minimum speed an object without propulsion, at that position, needs to have to move away indefinitely from the source of the field, as opposed to falling back or staying in an orbit within a... In astronomy, a rotation period is the time an astronomical object takes to complete one revolution around its rotation axis. ... An asteroid is a small, solid object in our Solar System, orbiting the Sun. ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standardized distance away. ... The albedo is a measure of reflectivity of a surface or body. ... Temperature is the physical property of a system which underlies the common notions of hot and cold; the material with the higher temperature is said to be hotter. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... Palomar Observatory is a privately-owned observatory located in San Diego County, California, 90 miles (145 km) southeast of Mount Wilson Observatory, on Palomar Mountain. ... June 20 is the 171st day of the year (172nd in leap years) in the Gregorian Calendar, with 194 days remaining. ... 1990 is a common year starting on Monday of the Gregorian calendar. ... Mars is the fourth planet from the Sun in the solar system, named after the Roman god of war (the counterpart of the Greek Ares), on account of its blood red color as viewed in the night sky. ... Image of the Trojan asteroids in front of and behind Jupiter along its orbital path. ... The Lagrangian points, (also Lagrange point, L-point, or libration point) are the five positions in space where a small object can be stationary with respect to two larger objects (such as a satellite with respect to the Earth and Moon). ... 1850 was a common year starting on Tuesday (see link for calendar). ... (Redirected from 2400) (23rd century - 24th century - 25th century - more centuries) The 24th century (Gregorian Calendar) comprises the years 2301-2400. ... Earth, also known as the Earth, Terra, and (mostly in the 19th century) Tellus, is the third planet outward from the Sun. ... (*min temperature refers to cloud tops only) Atmospheric characteristics Atmospheric pressure 9. ... Atmospheric characteristics Atmospheric pressure 70 kPa Hydrogen ~86% Helium ~14% Methane 0. ...

Long-term numerical integration shows that the orbit is stable. Kimmo A. Innanen and Seppo Mikkola note that "contrary to intuition, there is clear empirical evidence for the stability of motion around the L₄ and L₅ points of all the terrestrial planets over a timeframe of several million years".

Since then, other Mars Trojans have been identified; namely 1999 UJ₇ at the L₄ point and 1998 VF₃₁, 2001 DH₄₇, 2001 FG₂₄, and 2001 FR₁₂₇ at the L₅ point. The co-orbitals 1998 QH₅₆ and 1998 SD₄ are not destined to remain as Trojans —they'll be perturbed away by Mars within the next 500,000 years or so.

Note however, that as of 2005, the Minor Planet Center does not officially recognize any asteroid as being a Mars Trojan [1]: "in light of some recent ill-informed speculations on an astronomy-related Yahoo group of which the MPC has been made aware, this [Martian Trojan] list is being removed for the foreseeable future." 2005 is a common year starting on Saturday of the Gregorian calendar. ... The Minor Planet Center operates at the Smithsonian Astrophysical Observatory (SAO), which is part of the Center for Astrophysics (CfA) along with the Harvard College Observatory (HCO). ... An asteroid is a small, solid object in our Solar System, orbiting the Sun. ...

The infrared spectrum for this asteroid is typical of an A-class asteroid, but the visual spectrum is consistent with an evolved form of achondrite called an angrite. A-class asteroids are tinted red in hue, with a moderate albedo. The asteroid is located deep within a stable lagrangian zone of Mars, which is considered indicative of a primordial origin —meaning the asteroid has most likely been in this orbit for much of the history of the solar system. Image of a small dog taken in mid-infrared (thermal) light (false color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than visible light, but shorter than microwave radiation. ... A-type asteroids are inner-belt asteroids that have a strong, broad 1 µm olivine feature and a very reddish spectrum shortwards of 0. ... An Achondrite is a stony meteorite that is made of material similar to terrestrial basalts. ... The albedo is a measure of reflectivity of a surface or body. ... Presentation of the Solar system (not to scale). ...

References

• IAUC 5045
• IAUC 5047
• IAUC 5067
• IAUC 5075
• A. S. Rivkin, R. P. Binzel, S. J. Bus, and J. A. Grier, Spectroscopy and Classification of Mars Trojan Asteroids, 2002, Bulletin of the American Astronomical Society, 34, #3.
• S. Tabachnik and N. W. Evans, Cartography for Martian Trojans, April 1999.

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