It was discovered on 12 September 1936, by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland.
[2] Sibelius is a member of the Flora family, one of the largest populations of stony asteroids in the entire main-belt.
[10] In October 2007, a rotational lightcurve of Sibelius was obtained from photometric observations taken by Petr Pravec at the Ondřejov Observatory in the Czech Republic.
[4][5][6][8][9] The Collaborative Asteroid Lightcurve Link adopts an albedo of 0.3191 and a diameter of 7.20 kilometers from Petr Pravec's revised WISE thermal observations.
[3][7] This minor planet was named for Jean Sibelius (1865–1957), Finnish violinist and composer of the late Romantic and early-modern periods.