Mikal-Evans, T;
Sing, DK;
Kataria, T;
Wakeford, HR;
Mayne, NJ;
Lewis, NK;
Barstow, JK;
(2020)
Confirmation of water emission in the dayside spectrum of the ultrahot Jupiter WASP-121b.
Monthly Notices of the Royal Astronomical Society
, 496
(2)
pp. 1638-1644.
10.1093/mnras/staa1628.
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Abstract
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 60 ppm across 28 spectroscopic channels spanning the 1.12–1.64μm wavelength range. This is a considerable improvement to the 90 ppm precision we achieved previously for a single eclipse observation using the same observing set-up. Combining these data with those reported at other wavelengths, a blackbody spectrum for WASP-121b is ruled out at >6σ confidence and we confirm the interpretation of previous retrieval analyses that found the data are best explained by a dayside thermal inversion. The updated spectrum clearly resolves the water emission band at 1.3–1.6μm, with higher signal-to-noise than before. It also fails to reproduce a bump in the spectrum at 1.25μm derived from the first eclipse observation, which had tentatively been attributed to VO emission. We conclude that the latter was either a statistical fluctuation or a systematic artefact specific to the first eclipse data set.
| Type: | Article |
|---|---|
| Title: | Confirmation of water emission in the dayside spectrum of the ultrahot Jupiter WASP-121b |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/staa1628 |
| Publisher version: | https://doi.org/10.1093/mnras/staa1628 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | techniques: spectroscopic, planets and satellites: atmospheres |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10116258 |
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