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Lothringer JD, Sing DK, Rustamkulov Z, Wakeford HR, Stevenson KB, Nikolov N, Lavvas P, Spake JJ, Winch AT. UV absorption by silicate cloud precursors in ultra-hot Jupiter WASP-178b. Nature 2022; 604:49-52. [PMID: 35388193 DOI: 10.1038/s41586-022-04453-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 01/24/2022] [Indexed: 11/09/2022]
Abstract
Aerosols have been found to be nearly ubiquitous in substellar atmospheres1-3. The precise temperature at which these aerosols begin to form in exoplanets has yet to be observationally constrained. Theoretical models and observations of muted spectral features indicate that silicate clouds play an important role in exoplanets between at least 950 and 2,100 K (ref. 4). Some giant planets, however, are thought to be hot enough to avoid condensation altogether5,6. Here we report the near-ultraviolet transmission spectrum of the ultra-hot Jupiter WASP-178b (approximately 2,450 K), which exhibits substantial absorption. Bayesian retrievals indicate the presence of gaseous refractory species containing silicon and magnesium, which are the precursors to condensate clouds at lower temperatures. SiO, in particular, has not previously, to our knowledge, been detected in exoplanets, but the presence of SiO in WASP-178b is consistent with theoretical expectations as the dominant Si-bearing species at high temperatures. These observations allow us to re-interpret previous observations of HAT-P-41b and WASP-121b that did not consider SiO, to suggest that silicate cloud formation begins on exoplanets with equilibrium temperatures between 1,950 and 2,450 K.
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Affiliation(s)
- Joshua D Lothringer
- Department of Physics, Utah Valley University, Orem, UT, USA. .,Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA.
| | - David K Sing
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA. .,Department of Earth & Planetary Sciences, Johns Hopkins University, Baltimore, MD, USA.
| | - Zafar Rustamkulov
- Department of Earth & Planetary Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Hannah R Wakeford
- School of Physics, University of Bristol, HH Wills Physics Laboratory, Bristol, UK
| | - Kevin B Stevenson
- Department of Earth & Planetary Sciences, Johns Hopkins University, Baltimore, MD, USA.,Applied Physics Laboratory, Johns Hopkins University, Laurel, MD, USA
| | | | - Panayotis Lavvas
- Groupe de Spectrométrie Moléculaire et Atmosphérique, Université de Reims, Champagne-Ardenne, CNRS UMR F-7331, Reims, France
| | - Jessica J Spake
- Department of Astronomy, California Institute of Technology, Pasadena, CA, USA
| | - Autumn T Winch
- Department of Physics, Bryn Mawr College, Bryn Mawr, PA, USA
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Sousa-Silva C, Petkowski JJ, Seager S. Molecular simulations for the spectroscopic detection of atmospheric gases. Phys Chem Chem Phys 2019; 21:18970-18987. [DOI: 10.1039/c8cp07057a] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The remote identification of molecules in an atmosphere requires data for each gas that makes contributions to its spectra. We present a database of approximate spectra for thousands of volatiles, simulated using organic and quantum chemistry.
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Affiliation(s)
- Clara Sousa-Silva
- Department of Earth, Atmospheric, and Planetary Sciences
- Massachusetts Institute of Technology
- Cambridge
- USA
| | - Janusz J. Petkowski
- Department of Earth, Atmospheric, and Planetary Sciences
- Massachusetts Institute of Technology
- Cambridge
- USA
| | - Sara Seager
- Department of Earth, Atmospheric, and Planetary Sciences
- Massachusetts Institute of Technology
- Cambridge
- USA
- Department of Physics
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