Report by the ESA-ESO Working Group on Extra-Solar Planets

TL;DR

This report reviews the upcoming decade's strategies and expected advancements in exoplanet detection techniques, emphasizing space and ground-based missions, and discusses future ambitious projects aiming to detect Earth-like planets and signs of life.

Contribution

It provides a comprehensive overview of planned and proposed exoplanet detection methods, missions, and technological developments from 2005 to beyond 2015, highlighting the roles of ESA and ESO.

Findings

Hundreds of terrestrial planets expected from transit measurements.

Thousands of Jupiter-mass planets expected from astrometric measurements.

Future missions aim for direct detection of Earth-mass planets and potential signs of life.

Abstract

Various techniques are being used to search for extra-solar planetary signatures, including accurate measurement of radial velocity and positional (astrometric) displacements, gravitational microlensing, and photometric transits. Planned space experiments promise a considerable increase in the detections and statistical knowledge arising especially from transit and astrometric measurements over the years 2005-15, with some hundreds of terrestrial-type planets expected from transit measurements, and many thousands of Jupiter-mass planets expected from astrometric measurements. Beyond 2015, very ambitious space (Darwin/TPF) and ground (OWL) experiments are targeting direct detection of nearby Earth-mass planets in the habitable zone and the measurement of their spectral characteristics. Beyond these, `Life Finder' (aiming to produce confirmatory evidence of the presence of life) and `Earth Imager' (some massive interferometric array providing resolved images of a distant Earth) appear as distant visions. This report, to ESA and ESO, summarises the direction of exo-planet research that can be expected over the next 10 years or so, identifies the roles of the major facilities of the two organisations in the field, and concludes with some recommendations which may assist development of the field. The report has been compiled by the Working Group members and experts over the period June-December 2004.