Changeat, Q;
Skinner, JW;
Cho, JY-K;
Nättilä, J;
Waldmann, IP;
Al-Refaie, AF;
Dyrek, A;
... Yip, KH; + view all
(2024)
Is the Atmosphere of the Ultra-hot Jupiter WASP-121 b Variable?
The Astrophysical Journal Supplement Series
, 270
(2)
, Article 34. 10.3847/1538-4365/ad1191.
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Abstract
We present a comprehensive analysis of the Hubble Space Telescope observations of the atmosphere of WASP121 b, an ultra-hot Jupiter. After reducing the transit, eclipse, and phase-curve observations with a uniform methodology and addressing the biases from instrument systematics, sophisticated atmospheric retrievals are used to extract robust constraints on the thermal structure, chemistry, and cloud properties of the atmosphere. Our analysis shows that the observations are consistent with a strong thermal inversion beginning at ∼104 Pa on the dayside, solar to subsolar metallicity Z (i.e., -0.77 log 0.05 < < ( ) Z ), and supersolar C/O ratio (i.e., 0.59 < C/O < 0.87). More importantly, utilizing the high signal-to-noise ratio and repeated observations of the planet, we identify the following unambiguous time-varying signals in the data: (i) a shift of the putative hotspot offset between the two phase curves and (ii) varying spectral signatures in the transits and eclipses. By simulating the global dynamics of WASP-121 b's atmosphere at high resolution, we show that the identified signals are consistent with quasiperiodic weather patterns, hence atmospheric variability, with signatures at the level probed by the observations (∼5% to ∼10%) that change on a timescale of ∼5 planet days; in the simulations, the weather patterns arise from the formation and movement of storms and fronts, causing hot (as well as cold) patches of atmosphere to deform, separate, and mix in time.
| Type: | Article |
|---|---|
| Title: | Is the Atmosphere of the Ultra-hot Jupiter WASP-121 b Variable? |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/1538-4365/ad1191 |
| Publisher version: | http://dx.doi.org/10.3847/1538-4365/ad1191 |
| Language: | English |
| Additional information: | Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence, https://creativecommons.org/licenses/by/4.0/. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10186817 |
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