Its orbit is typical of Apollo asteroids and is characterized by significant eccentricity (0.54), low inclination (3.36º), and a semi-major axis of 1.65 AU.[10] Upon discovery, it was classified as an Earth crosser, a near-Earth asteroid (NEA) and a potentially hazardous asteroid (PHA) by the Minor Planet Center. It was listed on the Sentry Risk Table for less than one day.[11] Its orbit is in need of additional observations to determine if it is part of an asteroid family; as of October 2015 the orbit is determined using just twenty observations spanning an observation arc of 34 days.[3]2011 EO40 has an absolute magnitude of 21.5,[3] which gives a characteristic diameter of about 200 metres (660 ft).[6]
Recent calculations indicate that this object is a plausible candidate to be the parent body of the Chelyabinsk superbolide, since its orbit is very similar to the computed, pre-impact path of the Chelyabinsk meteoroid.[7][8][9] It has relatively frequent close encounters with Venus, the Earth–Moon system, and Mars. It had a close encounter with Earth on 28 January 2011 at 0.0953 AU (14,260,000 km; 8,860,000 mi),[3] and it will have a nominal Earth approach on 23 September 2025 at about 0.06 AU (9,000,000 km; 5,600,000 mi).[3] Asteroid 2011 EO40 experiences close approaches to the Earth–Moon system following a rather regular pattern, every 17 years approximately due to the combined action of multiple secular resonances.[8]
Future opposition windows are: 7 June 2016 at magnitude 24.5, and 28 May 2018 at magnitude 24.6. The best observation window will be on 2–23 September 2025.[3] Depending on the Earth approach distance (0.04–0.12 AU),[3] it should be brighter than magnitude 19.[12]
^ abde la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (21 November 2013). "The Chelyabinsk superbolide: a fragment of asteroid 2011 EO40?". Monthly Notices of the Royal Astronomical Society: Letters. 436 (1): L15–L19. arXiv:1307.7918. Bibcode:2013MNRAS.436L..15D. doi:10.1093/mnrasl/slt103.
^ abcde la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (1 September 2014). "Reconstructing the Chelyabinsk event: pre-impact orbital evolution". Monthly Notices of the Royal Astronomical Society: Letters. 443 (1): L39–L43. arXiv:1405.7202. Bibcode:2014MNRAS.443L..39D. doi:10.1093/mnrasl/slu078.
