68 research outputs found
Characteristic form of boost-invariant and cylindrically non-symmetric hydrodynamic equations
It is shown that the boost-invariant and cylindrically non-symmetric
hydrodynamic equations for baryon-free matter may be reduced to only two
coupled differential equations. In the case where the system exhibits the
cross-over phase transition, the standard numerical methods may be applied to
solve these equations and the proposed scheme allows for a very convenient
analysis of the cylindrically non-symmetric hydrodynamic expansion.Comment: 8 pages, 3 figures, 3 sets of figure
Titanium dioxide doped with vanadium as effective catalyst for selective oxidation of diphenyl sulfide to diphenyl sulfonate
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Nightside clouds and disequilibrium chemistry on the hot Jupiter WASP-43b
Hot Jupiters are among the best-studied exoplanets, but it is still poorly understood how their chemical composition and cloud properties vary with longitude. Theoretical models predict that clouds may condense on the nightside and that molecular abundances can be driven out of equilibrium by zonal winds. Here we report a phase-resolved emission spectrum of the hot Jupiter WASP-43b measured from 5 μm to 12 μm with the JWST’s Mid-Infrared Instrument. The spectra reveal a large day–night temperature contrast (with average brightness temperatures of 1,524 ± 35 K and 863 ± 23 K, respectively) and evidence for water absorption at all orbital phases. Comparisons with three-dimensional atmospheric models show that both the phase-curve shape and emission spectra strongly suggest the presence of nightside clouds that become optically thick to thermal emission at pressures greater than ~100 mbar. The dayside is consistent with a cloudless atmosphere above the mid-infrared photosphere. Contrary to expectations from equilibrium chemistry but consistent with disequilibrium kinetics models, methane is not detected on the nightside (2σ upper limit of 1–6 ppm, depending on model assumptions). Our results provide strong evidence that the atmosphere of WASP-43b is shaped by disequilibrium processes and provide new insights into the properties of the planet’s nightside clouds. However, the remaining discrepancies between our observations and our predictive atmospheric models emphasize the importance of further exploring the effects of clouds and disequilibrium chemistry in numerical models.Peer reviewe
Nightside clouds and disequilibrium chemistry on the hot Jupiter WASP-43b
Hot Jupiters are among the best-studied exoplanets, but it is still poorly understood how their chemical composition and cloud properties vary with longitude. Theoretical models predict that clouds may condense on the nightside and that molecular abundances can be driven out of equilibrium by zonal winds. Here we report a phase-resolved emission spectrum of the hot Jupiter WASP-43b measured from 5-12 μm with JWST's Mid-Infrared Instrument (MIRI). The spectra reveal a large day-night temperature contrast (with average brightness temperatures of 1524±35 and 863±23 Kelvin, respectively) and evidence for water absorption at all orbital phases. Comparisons with three-dimensional atmospheric models show that both the phase curve shape and emission spectra strongly suggest the presence of nightside clouds which become optically thick to thermal emission at pressures greater than ~100 mbar. The dayside is consistent with a cloudless atmosphere above the mid-infrared photosphere. Contrary to expectations from equilibrium chemistry but consistent with disequilibrium kinetics models, methane is not detected on the nightside (2σ upper limit of 1-6 parts per million, depending on model assumptions)
Nightside clouds and disequilibrium chemistry on the hot Jupiter WASP-43b
Hot Jupiters are among the best-studied exoplanets, but it is still poorly
understood how their chemical composition and cloud properties vary with
longitude. Theoretical models predict that clouds may condense on the nightside
and that molecular abundances can be driven out of equilibrium by zonal winds.
Here we report a phase-resolved emission spectrum of the hot Jupiter WASP-43b
measured from 5-12 m with JWST's Mid-Infrared Instrument (MIRI). The
spectra reveal a large day-night temperature contrast (with average brightness
temperatures of 152435 and 86323 Kelvin, respectively) and evidence
for water absorption at all orbital phases. Comparisons with three-dimensional
atmospheric models show that both the phase curve shape and emission spectra
strongly suggest the presence of nightside clouds which become optically thick
to thermal emission at pressures greater than ~100 mbar. The dayside is
consistent with a cloudless atmosphere above the mid-infrared photosphere.
Contrary to expectations from equilibrium chemistry but consistent with
disequilibrium kinetics models, methane is not detected on the nightside
(2 upper limit of 1-6 parts per million, depending on model
assumptions).Comment: 61 pages, 13 figures, 4 tables. This preprint has been submitted to
and accepted in principle for publication in Nature Astronomy without
significant change
EPR Investigation of Redox Processes Occurring upon Oxygen and Propylene Interaction with V2O5 and V2O5-MoO3
Quantitative EPR studies of transition metal ions in oxide, aluminosilicate and polymer matrices
Role of atomic oxygen(1-) ions in charge-transfer reactions at the surface of silica-supported molybdenum catalysts prepared by the grafting method
EPR studies on the formation of atomic oxygen(1-) (O-) ions on reduced silica-supported molybdenum catalysts prepared by the grafting method
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