2014 OL339
is an Aten asteroid that is a temporary quasi-satellite of Earth, the fourth known Earth quasi-satellite.
Discovery
was discovered on 29 July 2014 by Farid Char of the Chilean University of Antofagasta. The actual observers were O. Vaduvescu and V. Tudor, observing from the Roque de los Muchachos Observatory for the EURONEAR project with the Isaac Newton Telescope. The intended target of the program was the Apollo asteroid but F. Char identified as a streak near the edge of the observed field. As of 14 August 2015, it has been observed 39 times with an observation arc of 381 days.Orbit and orbital evolution
is currently an Aten asteroid. Its semi-major axis is similar to that of Earth, but it has a relatively high eccentricity and moderate orbital inclination. Gravitational interaction with Earth causes its orbit to change so that its average period is one year Its mean longitude is similar to that of Earth, which means that it is fairly close to Earth. This makes it a quasi-satellite. It moves in a kidney-shaped path going from east to west relative to Earth. The relative mean longitude compared to Earth librates around zero. This means that the center of the "kidney" moves back and forth over a period of years, from being in front of Earth to being behind Earth, but this movement is centered on Earth.It became a quasi-satellite at least 775 years ago and will stop being that 165 years from now after a "close" encounter with Earth. This quasi-satellite episode will have had a duration of around a thousand years or more, but less than 2,500 years. Before and after this episode it passes in and out of other types of co-orbital orbits, such as being a trojan or a "passing object".