Infrared spectrophotometry of the NEAR flyby target 253 Mathilde

Abstract

We have performed spectrophotometry of the Near-Earth Asteroid Rendezvous flyby target 253 Mathilde using five filters from 1.25 to 3.35 μn. We present a synthesized spectrum of ground-based data for 253 Mathilde from 0.3 to 3.35 μm combining our data with those of R. P. Binzel et al. (1996, Icarus 119, 447-449). We find 253 Mathilde to have a spectrum consistent with C-class asteroids in the near-IR, though without the 3-μm water-of-hydration feature commonly (but not always) seen on asteroids of this class. We compare Mathilde with plausible meteorite analogs, and find that the surface of this asteroid is not consistent with a surface composition of common carbonaceous chondritic material. We suggest some alternative analogs on the basis of comparison of meteorite data with a synthesis of ground-based observations of Mathilde. © 1997 Academic Press.