Theia : science cases and mission profiles for high precision astrometry in the future

TL;DR

The paper discusses the scientific potential and mission designs for a future high-precision astrometry mission, surpassing Gaia, to study dark matter and exoplanets with flexible pointing and accurate differential measurements.

Contribution

It presents new science cases, evaluates mission profiles with current technology, and details differential astrometry techniques for future high-precision space missions.

Findings

High-precision astrometry can revolutionize dark matter research.

Flexible pointing is feasible with current space technology.

Differential measurements enable ultimate accuracy without extreme stability constraints.

Abstract

High-precision astrometry well beyond the capacities of Gaia will provide a unique way to achieve astrophysical breakthroughs, in particular on the nature of dark matter, and a complete survey of nearby habitable exoplanets. In this contribution, we present the scientific cases that require a flexibly-pointing instrument capable of high astrometric accuracy and we review the best mission profiles that can achieve such observations with the current space technology as well as within the boundary conditions defined by space agencies. We also describe the way the differential astrometric measurement is made using reference stars within the field. We show that the ultimate accuracy can be met without drastic constrains on the telescope stability.