(523731)_2014_OK394
(523731) 2014 OK394 (provisional designation 1995 SN55) is a trans-Neptunian object that orbits in the outer Solar System beyond the orbit of Neptune. First observed as 1995 SN55 by Spacewatch on 20 September 1995, it was a lost minor planet with an insufficiently defined orbit with only 36 days of observations.[9] On 8 October 2010, it was rediscovered by the Pan-STARRS 1 survey and later announced as 2014 OK394 in July 2016.[1] It was not until November 2020 when amateur astronomers S. Deen and K. Ly identified 2014 OK394 and 1995 SN55 as the same object.[10] This identification was confirmed and announced by the Minor Planet Center in January 2021.[11]
Once thought to be a centaur crossing the orbits of the gas giants,[9] 1995 SN55 is now known to be a trans-Neptunian object in a 3:5 orbital resonance with Neptune.[4] With an estimated diameter between 160–280 kilometers (99–170 miles), it was formerly considered one of the largest centaurs.[7][12][13]