A NEAR-INFRARED TRANSMISSION SPECTRUM FOR THE WARM SATURN HAT-P-12b

作者：Line Michael R^*; Knutson Heather; Deming Drake; Wilkins Ashlee; Desert Jean Michel

来源：Astrophysical Journal, 2013, 778(2): 183.

DOI：10.1088/0004-637X/778/2/183

• planets and satellites: atmospheres
• planets and satellites: individual (HAT-P-12b)

We present a Hubble Space Telescope Wide Field Camera-3 (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 exoplanetary atmospheres.

• 出版日期2013-12-1