Probing Exo-Earth's Atmospheres During Primary Eclipse Observations

Most models used to predict or fit exoplanet transmission spectra do not include all the effects of atmospheric refraction.

Namely, the angular size of the star with respect to the planet can limit the lowest altitude, or highest density, probed during primary eclipses, as no rays passing below this critical altitude can reach the observer. We discuss this geometrical effect of refraction and show that most habitable exo-Earths cannot be probed down to their surface.

We present 0.4-5.0micron model transmission spectra of Earth's atmosphere viewed as a transiting exoplanet, and show how atmospheric refraction modifies the transmission spectrum depending on the spectral type (O5-M9) of the host star. We demonstrate that refraction is another phenomenon that can potentially explain flat transmission spectra over some spectral regions.

Y. Betremieux (1) L. Kaltenegger (1,2) ((1) MPIA, Heidelberg, Germany (2) CfA, USA) (Submitted on 23 Dec 2013)

Comments: 16 pages, 11 Figures, 2 Tables Submitted to ApJ on December 23rd, 2013

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Cite as: arXiv:1312.6625 [astro-ph.EP] (or arXiv:1312.6625v1 [astro-ph.EP] for this version)

Submission history From: Yan Betremieux [v1] Mon, 23 Dec 2013 18:08:42 GMT (1806kb)

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