DIRECT IMAGING DETECTION OF METHANE IN THE ATMOSPHERE OF GJ 504 b
- Astrophysics Research Centre, Queen's University Belfast, University Road, BT7 1NN Belfast (United Kingdom)
- Department of Astrophysical Sciences, Princeton University, NJ 08544 (United States)
- Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
- Astrophysics Department, Institute for Advanced Study, Princeton, NJ 08540 (United States)
- Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093-CH Zurich (Switzerland)
- Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H8 (Canada)
- Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)
- Division of Particle and Astrophysical Science, Nagoya University, Furo-Cho, Chikusa, Nagoya 464-8602 (Japan)
- National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
- Subaru Telescope, 650 North Aohoku Place, Hilo, HI 96720 (United States)
- Laboratoire Lagrange, UMR7239, University of Nice-Sophia Antipolis, CNRS, Observatoire de la Cote d'Azur, F-06300 Nice (France)
- Department of Physics and Astronomy, College of Charleston, 58 Coming Street, Charleston, SC 29424 (United States)
- Universitäts-Sternwarte München, Ludwig-Maximilians-Universität, Scheinerstr. 1, D-81679 Munich (Germany)
Most exoplanets detected by direct imaging thus far have been characterized by relatively hot (≳1000 K) and cloudy atmospheres. A surprising feature in some of their atmospheres has been a distinct lack of methane, possibly implying non-equilibrium chemistry. Recently, we reported the discovery of a planetary companion to the Sun-like star GJ 504 using Subaru/HiCIAO within the Strategic Exploration of Exoplanets and Disks with Subaru survey. The planet is substantially colder (<600 K) than previously imaged planets, and has indications of fewer clouds, which implies that it represents a new class of planetary atmospheres with expected similarities to late T-type brown dwarfs in the same temperature range. If so, one might also expect the presence of significant methane absorption, which is characteristic of such objects. Here, we report the detection of deep methane absorption in the atmosphere of GJ 504 b, using the Spectral Differential Imaging mode of HiCIAO to distinguish the absorption features around 1.6 μm. We also report updated JHK photometry based on new K {sub s}-band data and a re-analysis of the existing data. The results support the notion that GJ 504 b has atmospheric properties distinct from other imaged exoplanets, and will become a useful reference object for future planets in the same temperature range.
- OSTI ID:
- 22364143
- Journal Information:
- Astrophysical Journal Letters, Vol. 778, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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