English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Context. Over the past decades, several interplanetary missions have studiedsmall bodies in situ, leading to major advances in our understanding of theirgeological and geophysical properties. These missions, however, have had alimited number of targets. Among them, the NASA Dawn mission has characterisedin detail the topography and albedo variegation across the surface of asteroid(4) Vesta down to a spatial resolution of approximately 20 m/pixel scale.  Aims. Here our aim was to determine how much topographic and albedoinformation can be retrieved from the ground with VLT/SPHERE in the case ofVesta, having a former space mission (Dawn) providing us with the ground truththat can be used as a benchmark.  Methods. We observed Vesta with VLT/SPHERE/ZIMPOL as part of our ESO largeprogramme (ID 199.C-0074) at six different epochs, and deconvolved thecollected images with a parametric point spread function (PSF). We thencompared our images with synthetic views of Vesta generated from the 3D shapemodel of the Dawn mission, on which we projected Vesta's albedo information.  Results. We show that the deconvolution of the VLT/SPHERE images with aparametric PSF allows the retrieval of the main topographic and albedo featurespresent across the surface of Vesta down to a spatial resolution ofapproximately 20-30 km. Contour extraction shows an accuracy of approximately 1pixel (3.6 mas). The present study provides the very first quantitativeestimate of the accuracy of ground-based adaptive-optics imaging observationsof asteroid surfaces.  Conclusions. In the case of Vesta, the upcoming generation of 30-40mtelescopes (ELT, TMT, GMT) should in principle be able to resolve all of themain features present across its surface, including the troughs and thenorth-south crater dichotomy, provided that they operate at the diffractionlimit.

Closing the gap between Earth-based and interplanetary mission observations: Vesta seen by VLT/SPHERE