5261 Eureka is the first Mars trojan discovered.[5] It was discovered by David H. Levy and Henry Holt at Palomar Observatory on 20 June 1990.[1] 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 Earth, Venus, and Jupiter, are 0.5, 0.8, and 3.5 AU, respectively.
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 the discovery of 5261 Eureka, the Minor Planet Center has recognized three other asteroids as Martian trojans: 1999 UJ7 at the L4 point, 1998 VF31 at the L5 point,[5] and 2007 NS2, also at the L5 point.[6] At least five other asteroids in near-1:1 resonances with Mars have been discovered, but they do not exhibit trojan behavior. They are 2001 FR127, 2001 FG24, (36017) 1999 ND43, 1998 QH56 and (152704) 1998 SD4. Due to close orbital similarities, most of the other, smaller, members of the L5 group are hypothesized to be fragments of 5261 Eureka that were detached after it was spun up by the YORP effect (consistent with its rotational period of 2.69 h).[7]
The infrared spectrum for 5261 Eureka is typical for an A-type 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.[citation needed]
^ abCite error: The named reference schmadel2003 was invoked but never defined (see the help page).
^"Eureka". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
^ abCite error: The named reference JPLSBDB was invoked but never defined (see the help page).
^ abcdeCite error: The named reference Rivkin2007 was invoked but never defined (see the help page).
^ ab"List of Martian Trojans". Retrieved 26 February 2011.
^MPEC 2007-O09 : 2007 NS2
^Lovett, R. (20 October 2017). "Sun's light touch explains asteroids flying in formation behind Mars". Science. doi:10.1126/science.aar2794.
5261Eureka is the first Mars trojan discovered. It was discovered by David H. Levy and Henry Holt at Palomar Observatory on 20 June 1990. It trails Mars...
numbers 5261Eureka, an asteroid co-orbital with Mars Constantan, also known as Eureka, a metal alloy Heureka, a science centre in Vantaa, Finland Eureka, the...
known objects, the Neptune trojans. Mars has four accepted Mars trojans: 5261Eureka, 1999 UJ7, 1998 VF31, and 2007 NS2. Saturn's moon Tethys has two smaller...
the same general principles. Mars has four known co-orbital asteroids (5261Eureka, 1999 UJ7, 1998 VF31, and 2007 NS2, all at the Lagrangian points), and...
be a primordial trojan like Eureka. Its spectrum suggests that it is an X-type asteroid, which is different from 5261Eureka and 1998 VF31 but compatible...
They may also be called Mars Lagrangian asteroids. (121514) 1999 UJ7 5261Eureka (101429) 1998 VF31 (311999) 2007 NS2 (385250) 2001 DH47, 2001 FG24, 2001...
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