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Astrometric Exoplanet Detection with Gaia

Author(s): Perryman, Michael; Hartman, Joel; Bakos, Gaspar Aron; Lindegren, Lennart

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Abstract: We provide a revised assessment of the number of exoplanets that should be discovered by Gaia astrometry, extending previous studies to a broader range of spectral types, distances, and magnitudes. Our assessment is based on a large representative sample of host stars from the TRILEGAL Galaxy population synthesis model, recent estimates of the exoplanet frequency distributions as a function of stellar type, and detailed simulation of the Gaia observations using the updated instrument performance and scanning law. We use two approaches to estimate detectable planetary systems: one based on the signal-to-noise ratio of the astrometric signature per field crossing, easily reproducible and allowing comparisons with previous estimates, and a new and more robust metric based on orbit fitting to the simulated satellite data. With some plausible assumptions on planet occurrences, we find that some 21,000 (±6000) high-mass (∼1–15MJ) long-period planets should be discovered out to distances of ∼500 pc for the nominal 5 yr mission (including at least 1000–1500 around M dwarfs out to 100 pc), rising to some 70,000 (±20,000) for a 10 yr mission. We indicate some of the expected features of this exoplanet population, amongst them ∼25–50 intermediate-period (P ∼ 2–3 yr) transiting systems.
Publication Date: 10-Dec-2014
Electronic Publication Date: 19-Nov-2014
Citation: Perryman, Michael, Hartman, Joel, Bakos, Gáspár Á, Lindegren, Lennart. (2014). Astrometric Exoplanet Detection with Gaia. \apj, 797 (14 - 14. doi:10.1088/0004-637X/797/1/14
DOI: doi:10.1088/0004-637X/797/1/14
Type of Material: Journal Article
Journal/Proceeding Title: Astrophysical Journal
Version: Final published version. Article is made available in OAR by the publisher's permission or policy.

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