The Astrometric Foundation of Astrophysics

TL;DR

This paper reviews the development and impact of ESA's astrometric satellites Hipparcos and Gaia on astrophysics, emphasizing their revolutionary role in precise measurements of celestial objects and discussing future directions including a potential Gaia successor.

Contribution

It provides an overview of the significance of astrometry from Hipparcos and Gaia and discusses future prospects for fundamental astrometry over the next 50 years.

Findings

Gaia has revolutionized astrometric measurements across astronomy.

Future missions are planned to extend and improve astrometric precision.

Astrometry underpins understanding of stars, galaxies, and dark matter.

Abstract

Astrophysical studies require a knowledge of very accurate positions, motions and distances of stars. A brief overview is given of the significance and development of astrometry by ESA's two astrometric satellites, Hipparcos and Gaia, launched in respectively 1989 and 2013. The astrometric foundation of all branches of astronomy from the solar system and stellar systems to compact galaxies, quasars and dark matter is being revolutionized by the observations from these satellites. The future of fundamental astrometry must be considered in a time frame of 50 years, therefore science issues for a Gaia successor mission in twenty years are discussed in an extensive report: "Absolute astrometry in the next 50 years" available at http://arxiv.org/abs/1408.2190