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arXiv · 1310.4796

A Near-Infrared Transmission Spectrum for the Warm Saturn HAT-P-12b

Michael R. Line·Heather Knutson·Drake Deming·Ashlee Wilkins·Jean-Michel Desert
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Abstract

We present a HST WFC3 transmission spectrum for the transiting exoplanet HAT-P-12b. This warm (1000 K) sub-Saturn-mass planet has a smaller mass and a lower temperature than the hot-Jupiters that have been studied so far. We find that the planet's measured transmission spectrum lacks the expected water absorption feature for a hydrogen-dominated atmosphere, and is instead best-described by a model with high-altitude clouds. Using a frequentist hypothesis testing procedure, we can rule out a hydrogen-dominated cloud free atmosphere to 4.9$\sigma$. When combined with other recent WFC3 studies, our observations suggest that clouds may be common in exo-planetary atmospheres.

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Michael R. Line, Heather Knutson, Drake Deming, Ashlee Wilkins, Jean-Michel Desert. 2013-10-17. A Near-Infrared Transmission Spectrum for the Warm Saturn HAT-P-12b. https://doi.org/10.1088/0004-637x%2F778%2F2%2F183

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