is an Apollo asteroid that is a temporary horseshoe companion to the Earth, the tenth known Earth horseshoe librator. A close encounter with the Earth on 14 December 2015 caused the value of the semi-major axis of to drift slowly upwards, and the object evolved from an Aten asteroid to an Apollo asteroid about a year after this close approach.
Discovery was discovered on 9 December 2015 by R. G. Matheny observing with the 1.5-m reflector telescope at the Mount Lemmon Survey.Discovery MPEC As of 6 December 2016, it has been observed 47 times with an observation arc of 363 days.
Orbit and orbital evolution is currently an Apollo asteroid (Earth-crossing but with a period greater than a year). Its semi-major axis (currently 1.00096 AU) is similar to that of Earth (1.00074 AU), but it has a relatively low eccentricity (0.18431) and moderate orbital inclination (7.640°). It alternates between being an Apollo asteroid and being an Aten asteroid, changing dynamical status approximately every 130 years. As of 9 March 2016, this object is the 15th known Earth co-orbital and the 10th known object following a horseshoe path with respect to our planet. Asteroid follows an asymmetrical horseshoe path with respect to our planet; the value of its relative mean longitude oscillates about 180°, but enclosing 0°.
Physical properties With an absolute magnitude of 27.4, it has a diameter in the range of 9–22 meters (for an assumed albedo range of 0.20–0.04, respectively).
See also 54509 YORP
3753 Cruithne
Notes
References
Further reading Understanding the Distribution of Near-Earth Asteroids Bottke, W. F., Jedicke, R., Morbidelli, A., Petit, J.-M., Gladman, B. 2000, Science, Vol. 288, Issue 5474, pp. 2190–2194. A Numerical Survey of Transient Co-orbitals of the Terrestrial Planets Christou, A. A. 2000, Icarus, Vol. 144, Issue 1, pp. 1–20. Debiased Orbital and Absolute Magnitude Distribution of the Near-Earth Objects Bottke, W. F., Morbidelli, A., Jedicke, R., Petit, J.-M., Levison, H. F., Michel, P., Metcalfe, T. S. 2002, Icarus, Vol. 156, Issue 2, pp. 399–433. Transient co-orbital asteroids Brasser, R., Innanen, K. A., Connors, M., Veillet, C., Wiegert, P., Mikkola, S., Chodas, P. W. 2004, Icarus, Vol. 171, Issue 1, pp. 102–109. A trio of horseshoes: past, present and future dynamical evolution of Earth co-orbital asteroids 2015 XX169, 2015 YA and 2015 YQ1 de la Fuente Marcos, C., de la Fuente Marcos, R. 2016, Astrophysics and Space Science, Vol. 361, Issue 4, article 121 (13 pp.)
External links Discovery MPEC data at MPC ADS MPEC record Sciency Thoughts blog entry