文摘
We describe the first determination of thermal properties and size of the M-type Asteroid (16) Psyche from interferometric observations obtained with the Mid-Infrared Interferometric Instrument (MIDI) of the Very Large Telescope Interferometer. We used a thermophysical model to interpret our interferometric data. Our analysis shows that Psyche has a low macroscopic surface roughness. Using a convex 3-D shape model obtained by Kaasalainen et al. (Kaasalainen, M., Torppa, J., Piironen, J. [2002]. Icarus 159, 369-395), we derived a volume-equivalent diameter for (16) Psyche of 247 ¡À 25 km or 238 ¡À 24 km, depending on the possible values of surface roughness. Our corresponding thermal inertia estimates are 133 or 114 J m?2 s?0.5 K?1, with a total uncertainty estimated at 40 J m?2 s?0.5 K?1. They are among the highest thermal inertia values ever measured for an asteroid of this size. We consider this as a new evidence of a metal-rich surface for the Asteroid (16) Psyche.
