The Astronomical Journal (Jan 2023)
Characterizing a World Within the Hot-Neptune Desert: Transit Observations of LTT 9779 b with the Hubble Space Telescope/WFC3
- Billy Edwards,
- Quentin Changeat,
- Angelos Tsiaras,
- Andrew Allan,
- Patrick Behr,
- Simone R. Hagey,
- Michael D. Himes,
- Sushuang Ma,
- Keivan G. Stassun,
- Luis Thomas,
- Alexandra Thompson,
- Aaron Boley,
- Luke Booth,
- Jeroen Bouwman,
- Kevin France,
- Nataliea Lowson,
- Annabella Meech,
- Caprice L. Phillips,
- Aline A. Vidotto,
- Kai Hou Yip,
- Michelle Bieger,
- Amélie Gressier,
- Estelle Janin,
- Ing-Guey Jiang,
- Pietro Leonardi,
- Subhajit Sarkar,
- Nour Skaf,
- Jake Taylor,
- Ming Yang,
- Derek Ward-Thompson
Affiliations
- Billy Edwards
- ORCiD
- SRON, Netherlands Institute for Space Research , Niels Bohrweg 4, NL-2333 CA, Leiden, The Netherlands ; [email protected]; Department of Physics and Astronomy, University College London , Gower Street, London WC1E 6BT, UK
- Quentin Changeat
- ORCiD
- European Space Agency (ESA), ESA Office, Space Telescope Science Institute (STScI) , Baltimore, MD 21218, USA
- Angelos Tsiaras
- ORCiD
- INAF, Osservatorio Astrofisico di Arcetri , Largo E. Fermi 5, I-50125 Firenze, Italy
- Andrew Allan
- Leiden Observatory, Leiden University , PO Box 9513, 2300 RA Leiden, The Netherlands
- Patrick Behr
- ORCiD
- Laboratory for Atmospheric and Space Physics, University of Colorado Boulder , Boulder, CO 80303, USA
- Simone R. Hagey
- ORCiD
- The University of British Columbia , 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
- Michael D. Himes
- ORCiD
- Planetary Sciences Group, Department of Physics, University of Central Florida , Orlando, FL, USA; NASA Postdoctoral Program Fellow, NASA Goddard Space Flight Center , Greenbelt, MD, USA
- Sushuang Ma
- ORCiD
- Department of Physics and Astronomy, University College London , Gower Street, London WC1E 6BT, UK
- Keivan G. Stassun
- ORCiD
- Department of Physics and Astronomy, Vanderbilt University , Nashville, TN 37235, USA
- Luis Thomas
- Department of Physics and Astronomy, University College London , Gower Street, London WC1E 6BT, UK; Universitäts-Sternwarte München , Scheinerstr. 1, D-81679 München, Germany; Max-Planck-Institut für extraterrestrische Physik , Giessenbachstrasse 1, D-85748 Garching, Germany
- Alexandra Thompson
- ORCiD
- Department of Physics and Astronomy, University College London , Gower Street, London WC1E 6BT, UK
- Aaron Boley
- ORCiD
- The University of British Columbia , 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
- Luke Booth
- Cardiff Hub for Astrophysics Research and Technology (CHART), School of Physics and Astronomy, Cardiff University , Cardiff, UK
- Jeroen Bouwman
- Max-Planck-Institut für Astronomie , Königstuhl 17, D-69117 Heidelberg, Germany
- Kevin France
- ORCiD
- Laboratory for Atmospheric and Space Physics, University of Colorado Boulder , Boulder, CO 80303, USA
- Nataliea Lowson
- ORCiD
- Centre for Astrophysics, University of Southern Queensland , 499-565 West Street, Toowoomba, QLD 4350, Australia
- Annabella Meech
- ORCiD
- Department of Physics, University of Oxford , Denys Wilkinson Building, Oxford OX1 3RH, UK
- Caprice L. Phillips
- ORCiD
- Department of Astronomy, The Ohio State University , 100 W 18th Ave, Columbus, OH 43210, USA
- Aline A. Vidotto
- ORCiD
- Leiden Observatory, Leiden University , PO Box 9513, 2300 RA Leiden, The Netherlands
- Kai Hou Yip
- ORCiD
- Department of Physics and Astronomy, University College London , Gower Street, London WC1E 6BT, UK
- Michelle Bieger
- ORCiD
- College of Engineering, Mathematics and Physical Sciences, University of Exeter , North Park Road, Exeter, UK
- Amélie Gressier
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Estelle Janin
- Arizona State University , P.O. Box 871404, Tempe, AZ 85287-1404, USA
- Ing-Guey Jiang
- ORCiD
- Department of Physics and Institute of Astronomy, National Tsing Hua University , Hsinchu 30013, Taiwan
- Pietro Leonardi
- ORCiD
- Dipartimento di Fisica, Università di Trento , Via Sommarive 14, I-38123 Povo, Italy; Dipartimento di Fisica e Astronomia, Università degli Studi di Padova , Vicolo dell’Osservatorio 3, I-35122 Padova, Italy
- Subhajit Sarkar
- Cardiff Hub for Astrophysics Research and Technology (CHART), School of Physics and Astronomy, Cardiff University , Cardiff, UK
- Nour Skaf
- ORCiD
- Department of Physics and Astronomy, University College London , Gower Street, London WC1E 6BT, UK; LESIA, Observatoire de Paris, Univ. Paris Cité , Univ. PSL, CNRS, Sorbonne Univ., 5 pl. Jules Janssen, F-92195 Meudon, France; National Astronomical Observatory of Japan , Subaru Telescope, 650 North A’ohōkū Place, Hilo, HI 96720, USA
- Jake Taylor
- ORCiD
- Department of Physics (Atmospheric, Oceanic and Planetary Physics), University of Oxford , Parks Road, Oxford OX1 3PU, UK; Institut Trottier de Recherche sur les Exoplanètes and Département de Physique, Université de Montréal , 1375 Avenue Thérèse-Lavoie-Roux, Montréal, QC H2V 0B3, Canada
- Ming Yang
- ORCiD
- College of Surveying and Geo-Informatics, Tongji University , Shanghai 200092, People's Republic of China
- Derek Ward-Thompson
- ORCiD
- Jeremiah Horrocks Institute, University of Central Lancashire , Preston PR1 2HE, UK
- DOI
- https://doi.org/10.3847/1538-3881/acea77
- Journal volume & issue
-
Vol. 166,
no. 4
p. 158
Abstract
We present an atmospheric analysis of LTT 9779 b, a rare planet situated in the hot-Neptune desert, that has been observed with Hubble Space Telescope (HST)/WFC3 with G102 and G141. The combined transmission spectrum, which covers 0.8–1.6 μ m, shows a gradual increase in transit depth with wavelength. Our preferred atmospheric model shows evidence for H _2 O, CO _2 , and FeH with a significance of 3.1 σ , 2.4 σ , and 2.1 σ , respectively. In an attempt to constrain the rate of atmospheric escape for this planet, we search for the 1.083 μ m helium line in the G102 data but find no evidence of excess absorption that would indicate an escaping atmosphere using this tracer. We refine the orbital ephemerides of LTT 9779 b using our HST data and observations from TESS, searching for evidence of orbital decay or apsidal precession, which are not found. The phase-curve observation of LTT 9779 b with JWST NIRISS should provide deeper insights into the atmosphere of this planet and the expected atmospheric escape might be detected with further observations concentrated on other tracers such as Ly α .
Keywords
