Solar system science with Euclid

Description

The ESA Euclid mission has been designed to map the geometry of thedark Universe. Scheduled for launch in 2020, it will conduct asix-years visible and near-infrared imaging and spectroscopic surveyover 15,000 deg ^{2} down to V_{AB}˜24.5. Although the survey will avoidecliptic latitudes below 15°, the survey pattern in repeated sequencesof four broad-band filters seems well-adapted to Solar System objects(SSOs) detection and characterization.I will present a study of the impact of Euclid on planetary sciences.For that, I use current census of SSOs toextrapolate the total amount of SSOs detectable by Euclid, i.e.,within the survey area and brighter than the limiting magnitude. Foreach different population of SSO, from neighboring near-Earthasteroids to distant Kuiper-belt objects (KBOs) and including comets,With current survey design, about 150,000 SSOs,mainly from the asteroid main-belt, should be observed byEuclid. These objects will all have high inclination, which contrastswith many SSO surveys focusing on the ecliptic plane. There is apotential for discovery of several 10^4 SSOs by Euclid, in particulardistant KBOs at high declination, which will not be covered by LSST.I will present the expected Euclid astrometry, photometry, andspectroscopy with SSO properties to estimate how Euclid will constrainthe orbits of SSOs, their morphology (activity and multiplicity), physicalproperties (rotation period, spin orientation, and 3-D shape), andsurface composition. Euclid observations, consisting in asuite of four sequences of four measurements, will refine the spectralclassification of SSOs by extending the spectral coverage provided byGaia and the LSST to 2 microns. The time-resolved photometry, combined with sparse photometry such as measured by Gaia and the LSST,will contribute to the determination of SSO rotation period, spinorientation, and 3-D shape model. The sharp and stable point-spreadfunction of Euclid will also allow to resolve binary systems in theKuiper Belt and detect activity around Centaurs. In summary, the depth of Euclid survey (V_{AB}˜24.5),its spectral coverage (0.5 to 2.0 micron), and observation cadence hasgreat potential for Solar System research. A dedicated processing forSSOs is being set in place within Euclid consortium to produce catalogs of astrometry, multi-color andtime-resolved photometry, and spectral classification of some 10^5SSOs, delivered as Legacy Science.

Abstract

International audience

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