9969 Braille: Deep Space 1 infrared spectroscopy, geometric albedo, and classification

Abstract

Spectra of Asteroid 9969 Braille in the 1.25–2.6 µm region returned by the Deep Space 1 (DS1) Mission show a ~10% absorption band centered at 2 µm, and a reflectance peak at 1.6 µm. Analysis of these features suggest that the composition of Braille is roughly equal parts pyroxene and olivine. Its spectrum between 0.4 and 2.5 µm suggests that it is most closely related to the Q taxonomic type of asteroid. The spectrum also closely matches that of the ordinary chondrites, the most common type of terrestrial meteorite. The geometric albedo of Braille is unusually high (pv=0.34), which is also consistent with its placement within the rarer classes of stony asteroids, and which suggests it has a relatively fresh, unweathered surface, perhaps due to a recent collision.