Giant Outer Transiting Exoplanet Mass (GOT 'EM) Survey. II. Discovery of a Failed Hot Jupiter on a 2.7 Yr, Highly Eccentric Orbit
Abstract
Radial velocity (RV) surveys have discovered giant exoplanets on au-scale orbits with a broad distribution of eccentricities. Those with the most eccentric orbits are valuable laboratories for testing theories of high-eccentricity migration. However, few such exoplanets transit their host stars, thus removing the ability to apply constraints on formation from their bulk internal compositions. We report the discovery of Kepler-1704 b, a transiting 4.15 M_J giant planet on a 988.88 day orbit with an extreme eccentricity of 0.921_(-0.015)^(+0.010). Our decade-long RV baseline from the Keck I telescope allows us to measure the orbit and bulk heavy-element composition of Kepler-1704 b and place limits on the existence of undiscovered companions. A failed hot Jupiter, Kepler-1704 b was likely excited to high eccentricity by scattering events that possibly began during its gas accretion phase. Its final periastron distance was too large to allow for tidal circularization, so now it orbits its host from distances spanning 0.16–3.9 au. The maximum difference in planetary equilibrium temperature resulting from this elongated orbit is over 700 K. A simulation of the thermal phase curve of Kepler-1704 b during periastron passage demonstrates that it is a remarkable target for atmospheric characterization from the James Webb Space Telescope, which could potentially also measure the planet's rotational period as the hot spot from periastron rotates in and out of view. Continued characterization of the Kepler-1704 system promises to refine theories explaining the formation of hot Jupiters and cool giant planets like those in the solar system.
Additional Information
© 2021. The American Astronomical Society. Received 2021 March 10; revised 2021 June 28; accepted 2021 July 9; published 2021 September 21. The authors are grateful to the anonymous referee for a thorough review that improved the quality of this research. The authors thank all of the observers on the California Planet Search team for their many hours of hard work. The authors thank Ji Wang for a helpful discussion about PHARO AO imaging. The authors are grateful to Daniel Foreman-Mackey for a helpful discussion regarding exoplanet and photoeccentric modeling. The authors thank all of the members of the Unistellar Citizen Science campaign to observe Kepler-1704. P.D. is supported by a National Science Foundation (NSF) Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1903811. E.W.S. acknowledges support from the NASA Astrobiology Institute's Alternative Earths team funded under cooperative agreement No. NNA15BB03A and the Virtual Planetary Laboratory, which is a member of the NASA Nexus for Exoplanet System Science and funded via NASA Astrobiology Program grant No. 80NSSC18K0829. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This paper includes data collected by the Kepler mission and obtained from the MAST data archive at the Space Telescope Science Institute (STScI). Funding for the Kepler mission is provided by the NASA Science Mission Directorate. The STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 526555. This research has made use of the Exoplanet Follow-up Observation Program website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. Some of the Keck data were obtained under PI data awards 2013A and 2013B (M. Payne). Finally, the authors recognize and acknowledge the cultural role and reverence that the summit of Maunakea has within the indigenous Hawaiian community. We are deeply grateful to have the opportunity to conduct observations from this mountain. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. Facilities: Keck:I (HIRES) - , Keck:II (NIRC2) - , Kepler - , Hale (PHARO). - Software: astropy (Astropy Collaboration et al. 2013, 2018), corner (Foreman-Mackey 2016), EXOFASTv2 (Eastman et al. 2013, 2019; Eastman 2017), lightkurve (Lightkurve Collaboration et al. 2018), SpecMatch (Petigura 2015; Petigura et al. 2017), SpecMatch–Emp (Yee et al. 2017), exoplanet (Foreman-Mackey et al. 2020), pymc3 (Salvatier et al. 2016), theano (Theano Development Team 2016), REBOUND (Rein & Liu 2012), RVSearch (Rosenthal et al.2021).Attached Files
Published - Dalba_2021_AJ_162_154.pdf
Accepted Version - 2107.06901.pdf
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Additional details
- Eprint ID
- 111309
- Resolver ID
- CaltechAUTHORS:20211008-224604210
- AST-1903811
- NSF Astronomy and Astrophysics Fellowship
- NNA15BB03A
- NASA
- 80NSSC18K0829
- NASA
- NASA/JPL/Caltech
- NAS 5-26555
- NASA
- W. M. Keck Foundation
- Created
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2021-10-12Created from EPrint's datestamp field
- Updated
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2021-10-12Created from EPrint's last_modified field
- Caltech groups
- Astronomy Department, Infrared Processing and Analysis Center (IPAC)