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OATS-DAUT SEMINAR
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Speaker: Rafael Barrena (IAC, Spain)
Title: Earth's transmission spectrum from lunar eclipse observations
Date: Wednesday, May 12th, 2010
Time: 12:00
Venue: Villa Bazzoni
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Abstract:
Of the 342 planets so far discovered orbiting other stars, 58
`transit' the stellar disk, meaning that they can be detected through
a periodic decrease in the flux of starlight. The light from the star
passes through the atmosphere of the planet, and in a few cases the
basic atmospheric composition of the planet can be estimated. As we
get closer to finding analogues of Earth, an important consideration
for the characterization of extrasolar planetary atmospheres is what
the transmission spectrum of our planet looks like. Here we report the
optical and near-infrared transmission spectrum of the Earth, obtained
during a lunar eclipse. Some biologically relevant atmospheric
features that are weak in the reflection spectrum (such as ozone,
molecular oxygen, water, carbon dioxide and methane) are much stronger
in the transmission spectrum, and indeed stronger than predicted by
modelling. We also find the `fingerprints' of the Earth's ionosphere
and of the major atmospheric constituent, molecular nitrogen (N2),
which are missing in the reflection spectrum.
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contact: Marisa Girardi (UNI/TS)