13963 Euphrates (), provisional designation , is a resonant Griqua
asteroid
An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...
from the outer region of the
asteroid belt
The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids ...
, approximately 9 kilometers in diameter. It was discovered on 3 August 1991, by Belgian astronomer
Eric Elst
Eric Walter Elst (30 November 1936 – 2 January 2022) was a Belgian astronomer at the Royal Observatory of Belgium in Uccle and a prolific discoverer of asteroids. The Minor Planet Center ranks him among the top 10 discoverers of minor planets wi ...
at
ESO
The European Southern Observatory is an astronomical research organisation.
ESO may also refer to:
*Employee stock option (also: executive stock option)
*'' Ether Saga Odyssey'', a fantasy massively multiplayer online role-playing game
*''The Elde ...
's
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 also located at the site and are partly maintained by ESO. The observato ...
site in Chile. The asteroid was named after the
Euphrates
The Euphrates ( ; see #Etymology, below) is the longest and one of the most historically important rivers of West Asia. Tigris–Euphrates river system, Together with the Tigris, it is one of the two defining rivers of Mesopotamia (). Originati ...
River in the Middle East.
Orbit and classification
''Euphrates'' is one of very few bodies located in the 2:1
mean motion 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 the gas giant
Jupiter
Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...
and belongs to the "marginally unstable" Griqua group.
It orbits the Sun in the