TY - JOUR
T1 - LBT transmission spectroscopy of HAT-P-12b
T2 - Confirmation of a cloudy atmosphere with no significant alkali features
AU - Yan, F.
AU - Espinoza, N.
AU - Molaverdikhani, K.
AU - Henning, Th
AU - Mancini, L.
AU - Mallonn, M.
AU - Rackham, B. V.
AU - Apai, D.
AU - Jordán, A.
AU - Mollière, P.
AU - Chen, G.
AU - Carone, L.
AU - Reiners, A.
N1 - Funding Information:
G.C. acknowledges the support by the B-type Strategic Priority Program of the Chinese Academy of Sciences (Grant No. XDB41000000) and the Natural Science Foundation of Jiangsu Province (Grant No. BK20190110).
Publisher Copyright:
© ESO 2020.
PY - 2020/10/1
Y1 - 2020/10/1
N2 - The hot sub-Saturn-mass exoplanet HAT-P-12b is an ideal target for transmission spectroscopy because of its inflated radius. We observed one transit of the planet with the multi-object double spectrograph (MODS) on the Large Binocular Telescope (LBT) with the binocular mode and obtained an atmosphere transmission spectrum with a wavelength coverage of ∼0.4-0.9 μm. The spectrum is relatively flat and does not show any significant sodium or potassium absorption features. Our result is consistent with the revised Hubble Space Telescope (HST) transmission spectrum of a previous work, except that the HST result indicates a tentative detection of potassium. The potassium discrepancy could be the result of statistical fluctuation of the HST dataset. We fit the planetary transmission spectrum with an extensive grid of cloudy models and confirm the presence of high-altitude clouds in the planetary atmosphere. The fit was performed on the combined LBT and HST spectrum, which has an overall wavelength range of 0.4-1.6 μm. The LBT/MODS spectrograph has unique advantages in transmission spectroscopy observations because it can cover a wide wavelength range with a single exposure and acquire two sets of independent spectra simultaneously.
AB - The hot sub-Saturn-mass exoplanet HAT-P-12b is an ideal target for transmission spectroscopy because of its inflated radius. We observed one transit of the planet with the multi-object double spectrograph (MODS) on the Large Binocular Telescope (LBT) with the binocular mode and obtained an atmosphere transmission spectrum with a wavelength coverage of ∼0.4-0.9 μm. The spectrum is relatively flat and does not show any significant sodium or potassium absorption features. Our result is consistent with the revised Hubble Space Telescope (HST) transmission spectrum of a previous work, except that the HST result indicates a tentative detection of potassium. The potassium discrepancy could be the result of statistical fluctuation of the HST dataset. We fit the planetary transmission spectrum with an extensive grid of cloudy models and confirm the presence of high-altitude clouds in the planetary atmosphere. The fit was performed on the combined LBT and HST spectrum, which has an overall wavelength range of 0.4-1.6 μm. The LBT/MODS spectrograph has unique advantages in transmission spectroscopy observations because it can cover a wide wavelength range with a single exposure and acquire two sets of independent spectra simultaneously.
KW - Planets and satellites: atmospheres
KW - Planets and satellites: individual: HAT-P-12b
KW - Stars: atmospheres
KW - Techniques: spectroscopic
UR - http://www.scopus.com/inward/record.url?scp=85093985092&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201937265
DO - 10.1051/0004-6361/201937265
M3 - Article
AN - SCOPUS:85093985092
VL - 642
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
SN - 0004-6361
M1 - A98
ER -