555 Norma

Norma surface consists of more than 50% amorphous magnesium pyroxenes based on data collected with the Subaru Telescope.

[15] In April 2007, a first rotational lightcurve of Norma was obtained from photometric observations by French amateur astronomer Pierre Antonini.

[5][6][7][8][9][10][11] The Collaborative Asteroid Lightcurve Link (CALL) agrees with IRAS, and derives an albedo of 0.0528 and a diameter of 40.02 kilometers based on an absolute magnitude of 10.8.

CALL also assumes Norma to be a C-type asteroid (rather than a B-type) due to its derived low albedo and the general spectral type of the Themis family.

[4] This minor planet was named for the principal female character of the opera Norma by Italian composer Vincenzo Bellini (1801–1835).