3 research outputs found
Global Climate and Atmospheric Composition of the Ultra-Hot Jupiter WASP-103b from HST and Spitzer Phase Curve Observations
We present thermal phase curve measurements for the hot Jupiter WASP-103b
observed with Hubble/WFC3 and Spitzer/IRAC. The phase curves have large
amplitudes and negligible hotspot offsets, indicative of poor heat
redistribution to the nightside. We fit the phase variation with a range of
climate maps and find that a spherical harmonics model generally provides the
best fit. The phase-resolved spectra are consistent with blackbodies in the
WFC3 bandpass, with brightness temperatures ranging from K on the
nightside to K on the dayside. The dayside spectrum has a
significantly higher brightness temperature in the Spitzer bands, likely due to
CO emission and a thermal inversion. The inversion is not present on the
nightside. We retrieved the atmospheric composition and found the composition
is moderately metal-enriched ( solar)
and the carbon-to-oxygen ratio is below 0.9 at confidence. In
contrast to cooler hot Jupiters, we do not detect spectral features from water,
which we attribute to partial HO dissociation. We compare the phase curves
to 3D general circulation models and find magnetic drag effects are needed to
match the data. We also compare the WASP-103b spectra to brown dwarfs and young
directly imaged companions and find these objects have significantly larger
water features, indicating that surface gravity and irradiation environment
play an important role in shaping the spectra of hot Jupiters. These results
highlight the 3D structure of exoplanet atmospheres and illustrate the
importance of phase curve observations for understanding their complex
chemistry and physics.Comment: 25 pages, 17 figures, 7 tables; accepted to A
VLT/SPHERE Multiwavelength High-contrast Imaging of the HD 115600 Debris Disk: New Constraints on the Dust Geometry and the Presence of Young Giant Planets
International audienceYoung and dynamically active planetary systems can form disks of debris that are easier to image than the planets themselves. The morphology and evolution of these disks can help to infer the properties of the putative planets responsible for generating and shaping the debris structures. We present integral field spectroscopy and dual-band imaging from VLT/SPHERE (1.0-1.7 μm) of the debris disk around the young F2V/F3V star HD 115600. We aim to (1) characterize the geometry and composition of the debris ring, (2) search for thermal emission of young giant planets, and (3) in the absence of detected planets, to refine the inferred properties of plausible planets around HD 115600 to prepare future attempts to detect them. Using a different dust scattering model (ZODIPIC) than in the discovery paper to model the disk geometry, we find a 0 = 46 ± 2 au for the disk’s central radius and offsets Δα, Δδ = -1.0 ± 0.5, 0.5 ± 0.5 au. This offset is smaller than previously found, suggesting that unseen planets of lower masses could be sculpting the disk. Spectroscopy of the disk in Y-J bands with SPHERE shows reddish color, which becomes neutral or slightly blue in H-band seen with GPI, broadly consistent with a mixed bulk disk composition of processed organics and water ice. While our observed field contains numerous background objects at wide separations, no exoplanet has been directly observed to a mass sensitivity limit of 2 - 3(5 - 7) M J between a projected separation of 40 and 200 au for hot (cold)-start models