Detection of Na in the atmosphere of the hot Jupiter HAT-P-55b

Kang, Huiyi; Chen, Guo; Jiang, Chengzi; Pallé, Enric; Murgas, Felipe; Parviainen, Hannu; Ma, Yuehua; Fukui, Akihiko; Narita, Norio
Bibliographical reference

Astronomy and Astrophysics

Advertised on:
7
2024
Number of authors
9
IAC number of authors
5
Citations
0
Refereed citations
0
Description
The spectral signatures of optical absorbers, when combined with those of infrared molecules, play a critical role in constraining the cloud properties of exoplanet atmospheres. We aim to use optical transmission spectroscopy to confirm the tentative color signature previously observed by multiband photometry in the atmosphere of hot Jupiter HAT-P-55b. We observed a transit of the HAT-P-55b with the OSIRIS spectrograph on the Gran Telescopio Canarias (GTC). We created two sets of spectroscopic light curves, using the conventional band-integrated method and the newly proposed pixel-based method, to derive the transmission spectrum. We performed Bayesian spectral retrieval analyses on the transmission spectrum to interpret the observed atmospheric properties. The transmission spectra derived from the two methods are consistent, both spectrally resolving the tentative color signature observed by MuSCAT2. The retrievals on the combined OSIRIS and MuSCAT2 transmission spectrum yield a detection of Na at 5.5σ and a tentative detection of MgH at 3.4σ. The current optical-only wavelength coverage cannot constrain the absolute abundances of the atmospheric species. Space-based observations covering the molecular infrared bands or ground-based high-resolution spectroscopy are needed to further constrain the atmospheric properties of HAT-P-55b.
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Exoplanets and Astrobiology
The search for life in the universe has been driven by recent discoveries of planets around other stars (known as exoplanets), becoming one of the most active fields in modern astrophysics. The growing number of new exoplanets discovered in recent years and the recent advance on the study of their atmospheres are not only providing new valuable
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Pallé Bago