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A Hubble PanCET Study of HAT-P-11b: A Cloudy Neptune with a Low Atmospheric Metallicity
- Publication Year :
- 2019
-
Abstract
- We present the first comprehensive look at the $0.35-5$ $\mu$m transmission spectrum of the warm ($\sim 800$ K) Neptune HAT-P-11b derived from thirteen individual transits observed using the Hubble and Spitzer Space Telescopes. Along with the previously published molecular absorption feature in the $1.1-1.7$ $\mu$m bandpass, we detect a distinct absorption feature at 1.15 $\mu$m and a weak feature at 0.95 $\mu$m, indicating the presence of water and/or methane with a combined significance of 4.4 $\sigma$. We find that this planet's nearly flat optical transmission spectrum and attenuated near-infrared molecular absorption features are best-matched by models incorporating a high-altitude cloud layer. Atmospheric retrievals using the combined $0.35-1.7$ $\mu$m HST transmission spectrum yield strong constraints on atmospheric cloud-top pressure and metallicity, but we are unable to match the relatively shallow Spitzer transit depths without under-predicting the strength of the near-infrared molecular absorption bands. HAT-P-11b's HST transmission spectrum is well-matched by predictions from our microphysical cloud models. Both forward models and retrievals indicate that HAT-P-11b most likely has a relatively low atmospheric metallicity ($<br />Comment: Accepted for publication in AJ. 33 pages, 23 figures
- Subjects :
- Earth and Planetary Astrophysics (astro-ph.EP)
Physics
Solar System
010504 meteorology & atmospheric sciences
Metallicity
FOS: Physical sciences
Astronomy and Astrophysics
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
01 natural sciences
Wavelength
Transmission (telecommunications)
Space and Planetary Science
Neptune
Planet
0103 physical sciences
Transit (astronomy)
Astrophysics::Earth and Planetary Astrophysics
Absorption (electromagnetic radiation)
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
0105 earth and related environmental sciences
Astrophysics - Earth and Planetary Astrophysics
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....e940da87ef5728807d2c0608539d7081