Las Campañas Obs.
(471143) 2010 EK139
13.16 yr (4,808 days)
13 March 2010
Minor planet category
TNO · SDO · 2:7
A. Udalski S. S. Sheppard M. Kubiak C. Trujillo
(471143) 2010 EK139 is a trans-Neptunian object orbiting the Sun in the scattered disc. It was discovered on 13 March 2010, at the Chilean Las Campañas Observatory by astronomers Andrzej Udalski, Scott S. Sheppard, Marcin Kubiak and Chad Trujillo. The discovery was made during the Polish OGLE project of Warsaw University. Based on its absolute magnitude and assumed albedo, it is very likely a dwarf planet with a calculated diameter of approximately 470 kilometers.
The minor planet orbits the Sun at a distance of 32.6–107.8 AU once every 589 years and 10 months (215,426 days) and reach perihelion in 2038. Its orbit has a high eccentricity of 0.54 and an inclination of 29° with respect to the ecliptic. It It is currently 39.1 AU from the Sun.A ten-million-year integration of the orbit shows that this object is in a 2:7 resonance with Neptune.
The first precovery was taken by the Near-Earth Asteroid Tracking at Palomar Observatory in 2002, extending the minor planet's observation arc by 8 years prior to its discovery observation. Since then it has been observed 143 times over 6 oppositions and has an orbit quality of 1.
In 2010, the thermal radiation of 2010 EK139 was observed by the Herschel Space Telescope, which allowed astronomers to estimate its diameter at about 470 kilometres (290 mi).
Published in May 2013, a rotational light-curve for this minor planet was obtained from photometric observations at the discovering observatory with the 2.5-meter Irénée du Pont Telescope. It gave a rotation period of 7000707000000000000♠7.07±0.05 hours with a brightness variation of 0.12 magnitude (U=2).
Observations by American astronomer Michael Brown, using the Keck telescope in March 2012, suggest that there is no satellite, which makes determination of its mass impossible.