TY - JOUR
T1 - ACCESS
T2 - Tentative Detection of H2O in the Ground-based Optical Transmission Spectrum of the Low-density Hot Saturn HATS-5b
AU - Allen, Natalie H.
AU - Espinoza, Néstor
AU - Jordán, Andrés
AU - López-Morales, Mercedes
AU - Apai, Dániel
AU - Rackham, Benjamin V.
AU - Kirk, James
AU - Osip, David J.
AU - Weaver, Ian C.
AU - McGruder, Chima
AU - Ceballos, Kevin Ortiz
AU - Reggiani, Henrique
AU - Brahm, Rafael
AU - Rodler, Florian
AU - Lewis, Nikole K.
AU - Fraine, Jonathan
N1 - Funding Information: We thank our anonymous reviewer for their thoughtful and constructive comments and suggestions. This material is based on work supported by the National Science Foundation Graduate Research Fellowship under grant no. DGE1746891 (N.H.A) and No. DGE1745303 (C.M. and K.O.C.) and by a Ford Foundation Predoctoral Fellowship (K.O.C.). B.V.R. thanks the Heising-Simons Foundation for support. The results reported herein benefited from collaborations and/or information exchange within NASA's Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA's Science Mission Directorate. This material is partly based on work supported by the National Aeronautics and Space Administration under agreement No. 80NSSC21K0593 for the program “Alien Earths.” H.R. acknowledges support from a Carnegie Fellowship. R.B. acknowledges support from FONDECYT project 11200751 and from ANID—Millennium Science Initiative—ICN12_009. This paper includes data gathered with the 6.5 meter Magellan Telescope located at Las Campanas Observatory, Chile. We thank the staff at the Magellan Telescopes and Las Campanas Observatory for their ongoing input and support to make the ACCESS observations presented in this work possible. A.J. acknowledges support from ANID Millennium Science Initiative-ICN12009 and Fondecyt project 11200751 Funding Information: We thank our anonymous reviewer for their thoughtful and constructive comments and suggestions. This material is based on work supported by the National Science Foundation Graduate Research Fellowship under grant no. DGE1746891 (N.H.A) and No. DGE1745303 (C.M. and K.O.C.) and by a Ford Foundation Predoctoral Fellowship (K.O.C.). B.V.R. thanks the Heising-Simons Foundation for support. The results reported herein benefited from collaborations and/or information exchange within NASA's Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA's Science Mission Directorate. This material is partly based on work supported by the National Aeronautics and Space Administration under agreement No. 80NSSC21K0593 for the program “Alien Earths.” H.R. acknowledges support from a Carnegie Fellowship. R.B. acknowledges support from FONDECYT project 11200751 and from ANID—Millennium Science Initiative—ICN12_009. This paper includes data gathered with the 6.5 meter Magellan Telescope located at Las Campanas Observatory, Chile. We thank the staff at the Magellan Telescopes and Las Campanas Observatory for their ongoing input and support to make the ACCESS observations presented in this work possible. A.J. acknowledges support from ANID Millennium Science Initiative-ICN12009 and Fondecyt project 11200751 Publisher Copyright: © 2022. The Author(s). Published by the American Astronomical Society.
PY - 2022/10/1
Y1 - 2022/10/1
N2 - We present a precise ground-based optical transmission spectrum of the hot Saturn HATS-5b (T eq = 1025 K), obtained as part of the ACCESS survey with the IMACS multi-object spectrograph mounted on the Magellan Baade Telescope. Our spectra cover the 0.5-0.9 μm region and are the product of five individual transits observed between 2014 and 2018. We introduce the usage of additional second-order light in our analyses, which allows us to extract an “extra” transit light curve, improving the overall precision of our combined transit spectrum. We find that the favored atmospheric model for this transmission spectrum is a solar-metallicity atmosphere with subsolar C/O, whose features are dominated by H2O and with a depleted abundance of Na and K. If confirmed, this would point to a “clear” atmosphere at the pressure levels probed by transmission spectroscopy for HATS-5b. Our best-fit atmospheric model predicts a rich near-IR spectrum, which makes this exoplanet an excellent target for future follow-up observations with the James Webb Space Telescope, both to confirm this H2O detection and to superbly constrain the atmosphere’s parameters.
AB - We present a precise ground-based optical transmission spectrum of the hot Saturn HATS-5b (T eq = 1025 K), obtained as part of the ACCESS survey with the IMACS multi-object spectrograph mounted on the Magellan Baade Telescope. Our spectra cover the 0.5-0.9 μm region and are the product of five individual transits observed between 2014 and 2018. We introduce the usage of additional second-order light in our analyses, which allows us to extract an “extra” transit light curve, improving the overall precision of our combined transit spectrum. We find that the favored atmospheric model for this transmission spectrum is a solar-metallicity atmosphere with subsolar C/O, whose features are dominated by H2O and with a depleted abundance of Na and K. If confirmed, this would point to a “clear” atmosphere at the pressure levels probed by transmission spectroscopy for HATS-5b. Our best-fit atmospheric model predicts a rich near-IR spectrum, which makes this exoplanet an excellent target for future follow-up observations with the James Webb Space Telescope, both to confirm this H2O detection and to superbly constrain the atmosphere’s parameters.
UR - http://www.scopus.com/inward/record.url?scp=85139416343&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85139416343&partnerID=8YFLogxK
U2 - 10.3847/1538-3881/ac8b74
DO - 10.3847/1538-3881/ac8b74
M3 - Article
SN - 0004-6256
VL - 164
JO - Astronomical Journal
JF - Astronomical Journal
IS - 4
M1 - 153
ER -