TY - JOUR
T1 - The Hubble PanCET Program: Transit and Eclipse Spectroscopy of the Strongly Irradiated Giant Exoplanet WASP-76b
AU - Fu, Guangwei
AU - Deming, Drake
AU - Lothringer, Joshua
AU - Nikolov, Nikolay
AU - Sing, David K.
AU - Kempton, Eliza M.-R.
AU - Ih, Jegug
AU - Evans, Thomas M.
AU - Stevenson, Kevin
AU - Wakeford, H. R.
AU - Rodriguez, Joseph E.
AU - Eastman, Jason D.
AU - Stassun, Keivan
AU - Henry, Gregory W.
AU - López-Morales, Mercedes
AU - Lendl, Monika
AU - Conti, Dennis M.
AU - Stockdale, Chris
AU - Collins, Karen
AU - Kielkopf, John
AU - Barstow, Joanna K.
AU - Sanz-Forcada, Jorge
AU - Ehrenreich, David
AU - Bourrier, Vincent
AU - Santos, Leonardo A. dos
PY - 2021/9/1
Y1 - 2021/9/1
N2 - Ultra-hot Jupiters with equilibrium temperatures greater than 2000 K are uniquely interesting targets as they provide us crucial insights into how atmospheres behave under extreme conditions. This class of giant planets receives intense radiation from their host star and usually has strongly irradiated and highly inflated atmospheres. At such a high temperature, cloud formation is expected to be suppressed and thermal dissociation of water vapor could occur. We observed the ultra-hot Jupiter WASP-76b with seven transits and five eclipses using the Hubble Space Telescope and the Spitzer Space Telescope (Spitzer) for a comprehensive study of its atmospheric chemical and physical processes. We detected TiO and H2O absorption in the optical and near-infrared transit spectrum. Additional absorption by a number of neutral and ionized heavy metals like Fe, Ni, Ti, and SiO help explain the short-wavelength transit spectrum. The secondary eclipse spectrum shows muted water feature but a strong CO emission feature in Spitzer's 4.5 μm band indicating an inverted temperature pressure profile. We analyzed both the transit and eclipse spectra with a combination of self-consistent PHOENIX models and atmospheric retrieval. Both spectra were well fitted by the self-consistent PHOENIX forward atmosphere model in chemical and radiative equilibrium at solar metallicity, adding to the growing evidence that both TiO/VO and NUV heavy metals opacity are prominent NUV-optical opacity sources in the stratospheres of ultra-hot Jupiters.
AB - Ultra-hot Jupiters with equilibrium temperatures greater than 2000 K are uniquely interesting targets as they provide us crucial insights into how atmospheres behave under extreme conditions. This class of giant planets receives intense radiation from their host star and usually has strongly irradiated and highly inflated atmospheres. At such a high temperature, cloud formation is expected to be suppressed and thermal dissociation of water vapor could occur. We observed the ultra-hot Jupiter WASP-76b with seven transits and five eclipses using the Hubble Space Telescope and the Spitzer Space Telescope (Spitzer) for a comprehensive study of its atmospheric chemical and physical processes. We detected TiO and H2O absorption in the optical and near-infrared transit spectrum. Additional absorption by a number of neutral and ionized heavy metals like Fe, Ni, Ti, and SiO help explain the short-wavelength transit spectrum. The secondary eclipse spectrum shows muted water feature but a strong CO emission feature in Spitzer's 4.5 μm band indicating an inverted temperature pressure profile. We analyzed both the transit and eclipse spectra with a combination of self-consistent PHOENIX models and atmospheric retrieval. Both spectra were well fitted by the self-consistent PHOENIX forward atmosphere model in chemical and radiative equilibrium at solar metallicity, adding to the growing evidence that both TiO/VO and NUV heavy metals opacity are prominent NUV-optical opacity sources in the stratospheres of ultra-hot Jupiters.
UR - https://doi.org/10.3847/1538-3881/ac1200
U2 - 10.3847/1538-3881/ac1200
DO - 10.3847/1538-3881/ac1200
M3 - Article (Academic Journal)
VL - 162
JO - The Astronomical Journal
JF - The Astronomical Journal
IS - 108
ER -