P032-0008
Constraints on the formation and evolution of the largest main belt asteroids
Constraints on the formation and evolution of the largest main belt asteroids
Thursday, 10 December 2020
Poster
Abstract:
To make substantial progress in our understanding of the shape, internal compositional structure (i.e., density) and surface topography of large main belt asteroids, we have been carrying out an imaging survey with VLT/SPHERE via an ESO Large program (PI: P. Vernazza; ID: 199.C-0074) of a statistically significant fraction of all D>100 km main-belt asteroids (~40 out of ~200 asteroids; our survey covers the major compositional classes).
I will present an overview of the results obtained after 2.5 years of observations. So far, every target has challenged current knowledge, with for instance the linkage between an observed impact crater and a small collisional family (Vernazza et al. 2018), the first high angular resolution images of Psyche, target of a forthcoming NASA discovery mission (Viikinkoski et al. 2018, Ferrais et al. 2020), the bluffing view of asteroid (4) Vesta (Fetick et al. 2019), the homogeneous internal structure of CM-like asteroid (41) Daphne (Carry et al. 2019), the heavily cratered surface of Pallas (Marsset et al., 2020), the basin-free spherical shape of Hygiea while it suffered a giant impact that is at the origin of one of the largest asteroid families (Vernazza et al. 2020), and the nearly equilibrium shape of Interamnia (Hanus et al., 2020) to name a few. I will also present a review of the techniques employed to reach our science objectives (3D reconstruction & deconvolution of the reduced images). In particular, the 3D reconstruction algorithm MPCD (Jorda et al. 2016) developed in the framework of the Rosetta space mission has been successfully adapted to our VLT/SPHERE data whereas our deconvolution algorithm has successfully passed the test in the case of (4) Vesta (Fetick et al. 2019) although some residual artifacts imply that the technique can still be improved.
I will present an overview of the results obtained after 2.5 years of observations. So far, every target has challenged current knowledge, with for instance the linkage between an observed impact crater and a small collisional family (Vernazza et al. 2018), the first high angular resolution images of Psyche, target of a forthcoming NASA discovery mission (Viikinkoski et al. 2018, Ferrais et al. 2020), the bluffing view of asteroid (4) Vesta (Fetick et al. 2019), the homogeneous internal structure of CM-like asteroid (41) Daphne (Carry et al. 2019), the heavily cratered surface of Pallas (Marsset et al., 2020), the basin-free spherical shape of Hygiea while it suffered a giant impact that is at the origin of one of the largest asteroid families (Vernazza et al. 2020), and the nearly equilibrium shape of Interamnia (Hanus et al., 2020) to name a few. I will also present a review of the techniques employed to reach our science objectives (3D reconstruction & deconvolution of the reduced images). In particular, the 3D reconstruction algorithm MPCD (Jorda et al. 2016) developed in the framework of the Rosetta space mission has been successfully adapted to our VLT/SPHERE data whereas our deconvolution algorithm has successfully passed the test in the case of (4) Vesta (Fetick et al. 2019) although some residual artifacts imply that the technique can still be improved.