15 research outputs found
Recommended from our members
A featureless infrared transmission spectrum for the super-puff planet kepler-79d
A featureless infrared transmission spectrum for the super-puff planet kepler-79d
Extremely low density planets ('super-puffs') are a small but intriguing
subset of the transiting planet population. With masses in the super-Earth
range ( M) and radii akin to those of giant planets (
R), their large envelopes may have been accreted beyond the water
snow line and many appear to be susceptible to catastrophic mass loss. Both the
presence of water and the importance of mass loss can be explored using
transmission spectroscopy. Here, we present new HST WFC3 spectroscopy and
updated Kepler transit depth measurements for the super-puff Kepler-79d. We do
not detect any molecular absorption features in the m WFC3
bandpass and the combination of Kepler and WFC3 data are consistent with a flat
line model, indicating the presence of aerosols in the atmosphere. We compare
the shape of Kepler-79d's transmission spectrum to predictions from a
microphysical haze model that incorporates an outward particle flux due to
ongoing mass loss. We find that photochemical hazes offer an attractive
explanation for the observed properties of super-puffs like Kepler-79d, as they
simultaneously render the near-infrared spectrum featureless and reduce the
inferred envelope mass loss rate by moving the measured radius (optical depth
unity surface during transit) to lower pressures. We revisit the broader
question of mass loss rates for super-puffs and find that the age estimates and
mass loss rates for the majority of super-puffs can be reconciled if hazes move
the photosphere from the typically assumed pressure of mbar to bar
Accuracy of freehand pedicle screws versus lateral mass screws in the subaxial cervical spine
Recommended from our members
The Hubble PanCET Program: A Featureless Transmission Spectrum for WASP-29b and Evidence of Enhanced Atmospheric Metallicity on WASP-80b
We present a uniform analysis of transit observations from the Hubble Space Telescope and Spitzer Space Telescope of two warm gas giants orbiting K-type stars-WASP-29b and WASP-80b. The transmission spectra, which span 0.4-5.0 μm, are interpreted using a suite of chemical equilibrium PLATON atmospheric retrievals. Both planets show evidence of significant aerosol opacity along the day-night terminator. The spectrum of WASP-29b is flat throughout the visible and near-infrared, suggesting the presence of condensate clouds extending to low pressures. The lack of spectral features hinders our ability to constrain the atmospheric metallicity and C/O ratio. In contrast, WASP-80b shows a discernible, albeit muted H2O absorption feature at 1.4 μm, as well as a steep optical spectral slope that is caused by fine-particle aerosols and/or contamination from unocculted spots on the variable host star. WASP-80b joins the small number of gas-giant exoplanets that show evidence for enhanced atmospheric metallicity: The transmission spectrum is consistent with metallicities ranging from a1/430-100 times solar in the case of cloudy limbs to a few hundred times solar in the cloud-free scenario. In addition to the detection of water, we infer the presence of CO2 in the atmosphere of WASP-80b based on the enhanced transit depth in the Spitzer 4.5 μm bandpass. From a complementary analysis of Spitzer secondary eclipses, we find that the dayside emission from WASP-29b and WASP-80b is consistent with brightness temperatures of 937 ± 48 and 851 ± 14 K, respectively, indicating relatively weak day-night heat transport and low Bond albedo. © 2022. The Author(s). Published by the American Astronomical Society.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]