2005 RM43 is considered likely to be a dwarf planet by both Brown and Tancredi.[8][10] Based on an absolute magnitude of 4.4, the body's diameter could be anywhere in the range of 350 to 800 kilometres (km), depending on its albedo, the surface reflectivity of the object.[11] Johnston's Archive gives an estimate of 584 km, based on an assumed albedo of 0.09.[2] Brown estimates a diameter of 524 km, based on an absolute magnitude of 4.8 and an assumed albedo of 0.08. A stellar occultation by 2005 RM43 in December 2018 gave a minimum diameter of 458 km.[5]
In 2018, two stellar occultations by 2005 RM43 were observed on 3 February and 24 December.[3] Observations of the February occultation yielded a single chord length of 456 km (283 mi).[12] Observations of the December occultation yielded two positive chords, which suggest an approximate diameter of 644 km (400 mi) for 2005 RM43.[13]
^ ab"TNO Results". ERC Lucky Star Project. Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique (LESIA). Retrieved 13 July 2020.
^ abcdFarkas-Takács, A.; Kiss, Cs.; Vilenius, E.; Marton, G.; Müller, T. G.; Mommert, M.; et al. (28 February 2020). "TNOs are Cool! A Survey of the transneptunian Region XV. Physical characteristics of 23 resonant transneptunian and scattered disk objects". Astronomy & Astrophysics. A23: 638. arXiv:2002.12712. Bibcode:2020A&A...638A..23F. doi:10.1051/0004-6361/201936183. S2CID216193564.
^"Occultation by 2005 RM43 in 03 02 2018"(PDF). ERC Lucky Star Project. Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique (LESIA). 3 February 2018. Retrieved 13 July 2020.
^"Occultation by 2005 RM43 in 23 DEC 2018"(PDF). ERC Lucky Star Project. Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique (LESIA). 24 December 2018. Retrieved 13 July 2020.