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 1.65AU.[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 (660ft).[6]
Relationship to the Chelyabinsk superbolide
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 0.0953AU (14,260,000km; 8,860,000mi),[3] and it will have a nominal Earth approach on 23 September 2025 at about 0.06AU (9,000,000km; 5,600,000mi).[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]
Visibility
2011 EO40 had opposition windows on 7June 2016 at magnitude24.5, and 28May 2018 at magnitude24.6 but wasn't observed during either opposition.[10] The asteroid was recovered on 15August 2025 by Pan-STARRS.[12] The best observation window will be on 2–23September 2025.[3] Depending on the Earth approach distance (0.04–0.12AU),[3] it should be brighter than magnitude19.[13]
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