Constraining the reflective properties of WASP-178 b using CHEOPS photometry

Pagano, I.; Scandariato, G.; Singh, V.; Lendl, M.; Queloz, D.; Simon, Attila; Sousa, S. G.; Brandeker, A.; Cameron, A. Collier; Sulis, S.; Van Grootel, V.; Wilson, T. G.; Alibert, Y.; Alonso, R.; Anglada, G.; Bárczy, T.; Navascues, D. Barrado; Barros, S. C. C.; Baumjohann, W.; Beck, M.; ... (2024). Constraining the reflective properties of WASP-178 b using CHEOPS photometry. Astronomy and astrophysics, 682 EDP Sciences 10.1051/0004-6361/202346705

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Context. Multiwavelength photometry of the secondary eclipses of extrasolar planets is able to disentangle the reflected and thermally emitted light radiated from the planetary dayside. Based on this, we can measure the planetary geometric albedo Ag, which is an indicator of the presence of clouds in the atmosphere, and the recirculation efficiency ϵ, which quantifies the energy transport within the atmosphere.

Aims. We measure Ag and ϵ for the planet WASP-178 b, a highly irradiated giant planet with an estimated equilibrium temperature of 2450 K.

Methods. We analyzed archival spectra and the light curves collected by CHEOPS and TESS to characterize the host WASP-178, refine the ephemeris of the system, and measure the eclipse depth in the passbands of the two telescopes.

Results. We measured a marginally significant eclipse depth of 70 ± 40 ppm in the TESS passband, and a statistically significant depth of 70 ± 20 ppm in the CHEOPS passband.

Conclusions. Combining the eclipse-depth measurement in the CHEOPS (λeff = 6300 Å) and TESS (λeff = 8000 Å) passbands, we constrained the dayside brightness temperature of WASP-178 b in the 2250–2800 K interval. The geometric albedo 0.1< Ag<0.35 generally supports the picture that giant planets are poorly reflective, while the recirculation efficiency ϵ >0.7 makes WASP-178 b an interesting laboratory for testing the current heat-recirculation models.

Item Type:

Journal Article (Original Article)


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08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute
10 Strategic Research Centers > Center for Space and Habitability (CSH)
08 Faculty of Science > Physics Institute > NCCR PlanetS

UniBE Contributor:

Simon, Attila, Alibert, Yann Daniel Pierre, Beck, Thomas, Benz, Willy, Broeg, Christopher, Demory, Brice-Olivier Denys, Fortier, A., Mordasini, Christoph, Rieder, Martin, Thomas, Nicolas


000 Computer science, knowledge & systems
500 Science > 520 Astronomy
500 Science > 530 Physics
600 Technology > 620 Engineering




EDP Sciences




Danielle Zemp

Date Deposited:

04 Apr 2024 15:10

Last Modified:

05 Apr 2024 09:11

Publisher DOI:





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