- Press Release
- September 28, 2022
Confirmation Of Water Emission In The Dayside Spectrum Of The Ultrahot Jupiter WASP-121b
We present four new secondary eclipse observations for the ultrahot Jupiter WASP-121b acquired using the Hubble Space Telescope Wide Field Camera 3.
The eclipse depth is measured to a median precision of 60ppm across 28 spectroscopic channels spanning the 1.12-1.64 micron wavelength range. This is a considerable improvement to the 90ppm precision we achieved previously for a single eclipse observation using the same observing setup. Combining these data with those reported at other wavelengths, a blackbody spectrum for WASP-121b is ruled out at >6-sigma confidence and we confirm the interpretation of previous retrieval analyses that found the data is best explained by a dayside thermal inversion. The updated spectrum clearly resolves the water emission band at 1.3-1.6 micron, with higher signal-to-noise than before.
It also fails to reproduce a bump in the spectrum at 1.25 micron derived from the first eclipse observation, which had tentatively been attributed to VO emission. We conclude the latter was either a statistical fluctuation or a systematic artefact specific to the first eclipse dataset.
Thomas Mikal-Evans, David K. Sing, Tiffany Kataria, Hannah R. Wakeford, Nathan J. Mayne, Nikole K. Lewis, Joanna K. Barstow, Jessica J. Spake
Comments: Accepted in MNRAS
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2005.09631 [astro-ph.EP] (or arXiv:2005.09631v1 [astro-ph.EP] for this version)
From: Thomas Evans
[v1] Tue, 19 May 2020 17:58:14 UTC (274 KB)