Near-infrared compositional mapping of small solar system bodies with SINFONI

Team responsible: Christophe Dumas (ESO)


This program intends to get spatially resolved spectra of planetary surfaces (asteroids and satellites) of particular scientific int erest. In order to quantify the spatial heterogeneity of their surface composition the targets will be observed with two settings (J and H+K), and at several epochs in order to explore the full rotational phase-space.

Target list
NameRA(2000)DEC(2000)Plate-Scale(s)Bands(s)Exp.time(on source)
Vesta00h00-10deg25mas/pixJ, H+K60sec
Europa13h00-05deg25mas/pixJ, H+K60sec
Pallas12h30+05deg25mas/pixJ, H+K60sec
Ceres15h30-10deg25mas/pixJ, H+K60sec

Science Rationale
Asteroid Vesta: Visible from Aug 04 to Nov 04 under very good conditions from Paranal. Vesta is the only differentiated asteroid of the solar system that hasn't been entirely disrupted during impacts with other minor bodies. We propose to carryout a petrologic stu dy of this object by measuring the spatial distribution and abundances of the main surface minerals (pyroxene, olivine, feldspar). T he main result of this project will be to better understand whether Vesta is fully or partially differentiated, which will, in turn, give us some insights on how terrestrial-like bodies could form from the accretion of early planetesimals similar to Vesta.

Asteroid Pallas and Ceres: Visible respectively in the Mar-May 05 and Apr-Jun 05 periods. These objects are the two largest "wet" as teroids of the solar system. Their surfaces show alteration possibly due to the action of hydrated minerals. The SINFONI data will c omplement existing imaging data by investigating the spatial distribution and composition of the material present on Ceres and Palla s, and search, in particular, for the spectral signature of surface frost. These objects have possibly preserved, in their interior, a large quantity of water ice.

Jovian satellite Europa: Visible from Nov 04 to Mar 05. Recent observations of Europa carried-out from the ground and space with the Galileo spacecraft confirmed that the surface of the satellite is more complex than a pure assemblage of water ice. The SINFONI obs ervations will allow to characterize the spatial distribution of the non-water ice components. The spectral resolution provided by S INFONI is much larger than was obtained with Galileo/NIMS (R~100) and therefore will allow a better determination of the physical pr operties of the surface chemicals.