Fig. 3: Pressure-dependent atmospheric properties retrieved for WASP-121b.
From: Diurnal variations in the stratosphere of the ultrahot giant exoplanet WASP-121b
a, The green solid line shows the median temperature at each pressure level inferred for the dayside hemisphere by the ATMO retrieval analysis, with green shading showing the 1σ credible range. The purple solid line and purple shading show the same, but for the nightside hemisphere. Thick sections of the purple and green lines indicate the pressure levels from which the majority of the planetary emission is emanating at the wavelengths covered by the data. b,c, Vertical abundances for H2O and H−, using the same colour scheme as in a. The narrow range of allowed H2O abundances for the nightside is a result of the fixed metallicity. For H−, the nightside abundance is more uncertain than the dayside abundance, because no H− spectral features are detected in the nightside spectrum. However, the H− abundance can still vary under the assumption of chemical equilibrium within the range of allowed temperatures, as the latter mediates the abundance of free electrons through thermal ionization. d, Normalized contribution functions for the dayside and nightside hemispheres, integrated across the wavelength range covered by the data, using the same colour scheme as in a.
