Details

Autor(en) / Beteiligte

• Weaver, Ian C.
• López-Morales, Mercedes
• Alam, Munazza K.
• Espinoza, Néstor
• Rackham, Benjamin V.
• Goyal, Jayesh M.
• MacDonald, Ryan J.
• Lewis, Nikole K.
• Apai, Dániel
• Bixel, Alex
• Jordán, Andrés
• Kirk, James
• McGruder, Chima
• Osip, David J.

Titel

ACCESS: An Optical Transmission Spectrum of the High-gravity Hot Jupiter HAT-P-23b

Ist Teil von

• The Astronomical journal, 2021-06, Vol.161 (6), p.278

Ort / Verlag

Madison: The American Astronomical Society

Erscheinungsjahr

2021

Quelle

Elektronische Zeitschriftenbibliothek - Frei zugängliche E-Journals

Beschreibungen/Notizen

• Abstract We present a new ground-based visible transmission spectrum of the high-gravity, hot Jupiter HAT-P-23b, obtained as part of the ACCESS project. We derive the spectrum from five transits observed between 2016 and 2018, with combined wavelength coverage between 5200 Å and 9269 Å in 200 Å bins, and with a median precision of 247 ppm per bin. HAT-P-23b’s relatively high surface gravity ( g ≈ 30 m s −2 ), combined with updated stellar and planetary parameters from Gaia DR2, gives a five-scale-height signal of 384 ppm for a hydrogen-dominated atmosphere. Bayesian models favor a clear atmosphere for the planet with the tentative presence of TiO, after simultaneously modeling stellar contamination, using spots parameter constraints from photometry. If confirmed, HAT-P-23b would be the first example of a high-gravity gas giant with a clear atmosphere observed in transmission at optical/near-IR wavelengths; therefore, we recommend expanding observations to the UV and IR to confirm our results and further characterize this planet. This result demonstrates how combining transmission spectroscopy of exoplanet atmospheres with long-term photometric monitoring of the host stars can help disentangle the exoplanet and stellar activity signals.