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Telling twins apart: Exo-Earths and Venuses with transit spectroscopy

journal contribution
posted on 02.03.2016, 09:41 by J. K. Barstow, S. Aigrain, P. G. J. Irwin, S. Kendrew, Leigh Nicholas Fletcher
The planned launch of the James Webb Space Telescope in 2018 will herald a new era of exoplanet spectroscopy. JWST will be the first telescope sensitive enough to potentially characterize terrestrial planets from their transmission spectra. In this work, we explore the possibility that terrestrial planets with Venus -type and Earth-type atmospheres could be distinguished from each other using spectra obtained by JWST. If we find a terrestrial planet close to the liquid water habitable zone of an M5 star within a distance of 10 parsecs, it would be possible to detect atmospheric ozone if present in large enough quantities, which would enable an oxygen-rich atmosphere to be identified. However, the cloudiness of a Venus-type atmosphere would inhibit our ability to draw firm conclusions about the atmospheric composition, making any result ambiguous. Observing small, temperate planets with JWST requires significant investment of resources, with single targets requiring of order 100 transits to achieve sufficient signal to noise. The possibility of detecting a crucial feature such as the ozone signature would need to be carefully weighed against the likelihood of clouds obscuring gas absorption in the spectrum.

History

Citation

Monthly Notices Of The Royal Astronomical Society, 2016, 458 (3), pp. 2657-2666

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

VoR (Version of Record)

Published in

Monthly Notices Of The Royal Astronomical Society

issn

0035-8711

eissn

1365-2966

Acceptance date

28/02/2016

Copyright date

2016

Available date

02/03/2016

Publisher version

http://mnras.oxfordjournals.org/content/458/3/2657.abstract?sid=d8f723fc-efee-4643-8463-38a6b7350ec9

Notes

Deposited with reference to the publisher’s archiving policy available on the SHERPA/RoMEO website.

Language

en