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Proceedings Paper

The exoplanet program of the microarcsecond astrometric observatory Theia (Conference Presentation)
Author(s): Lucas Labadie; Fabien Malbet; Alain Léger; Céline Boehm; Antoine Crouzier; Alberto Krone-Martins

Paper Abstract

The Theia mission, as a natural successor to Gaia, will be the first extremely-high-precision astrometric surveyor that may emerge from the last ESA M5 call in October 2016. A major objective of Theia in the context of this conference is the detection by astrometry of Earths and Super-Earths exoplanets in the habitable zone of nearby A to M stars. This can be done by astrometry from space if a motion of <1-microarcesec can be recorded (0.3 microarcsec for an Earth/Sun system at 10 pc). Such an accuracy can be reached by Theia in the form of an 0.8-m telescope with 0.5° FOV in orbit at L2 for 3,5 years and providing repeated differential astrometric measurements between the science target and background reference stars. The exoplanet program will use circa 10% of the mission lifetime and will be able to survey 63 nearby stars with a ~0.6 microarssec astrometric floor to eventually detect planets down to 0.2 M_earth over circa 50 visits. In order to measure a centroid position on the CCD with an accuracy of 1e-5 pixels, Theia’s high-precision measurement relies on an on-board interferometric laser metrology unit to calibrate out the pixel’s offset to the nominal position, as well as the inter- and intra-pixel quantum efficiency. The preliminary Theia mission assessment allowed us to identify a safe and robust mission architecture that demonstrates the mission feasibility within the Soyuz ST launch envelope and a small M-class mission cost cap. We present here these features and the corresponding exoplanet program.

Paper Details

Date Published: 19 September 2017
Proc. SPIE 10400, Techniques and Instrumentation for Detection of Exoplanets VIII, 104001F (19 September 2017); doi: 10.1117/12.2273619
Show Author Affiliations
Lucas Labadie, Univ. zu Köln (Germany)
Fabien Malbet, Institut de Planétologie et d’Astrophysique de Grenoble (France)
Alain Léger, Institut d'Astrophysique Spatiale (France)
Céline Boehm, Durham Univ. (United Kingdom)
Antoine Crouzier, Institut de Planétologie et d’Astrophysique de Grenoble (France)
Alberto Krone-Martins, Univ. de Lisboa (Portugal)

Published in SPIE Proceedings Vol. 10400:
Techniques and Instrumentation for Detection of Exoplanets VIII
Stuart Shaklan, Editor(s)

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