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Evidence for Reflected Light from the Most Eccentric Exoplanet Known

Kane, Stephen R. and Wittenmyer, Robert A. and Hinkel, Natalie R. and Roy, Arpita and Mahadevan, Suvrath and Dragomir, Diana and Matthews, Jaymie M. and Henry, Gregory W. and Chakraborty, Abhijit and Boyajian, Tabetha S. and Wright, Jason T. and Ciardi, David R. and Fischer, Debra A. and Butler, R. Paul and Tinney, C. G. and Carter, Brad D. and Jones, Hugh R. A. and Bailey, Jeremy and O'Toole, Simon J. (2016) Evidence for Reflected Light from the Most Eccentric Exoplanet Known. Astrophysical Journal, 821 (1). Art. No. 65. ISSN 0004-637X.

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Planets in highly eccentric orbits form a class of objects not seen within our solar system. The most extreme case known among these objects is the planet orbiting HD 20782, with an orbital period of 597 days and an eccentricity of 0.96. Here we present new data and analysis for this system as part of the Transit Ephemeris Refinement and Monitoring Survey. We obtained CHIRON spectra to perform an independent estimation of the fundamental stellar parameters. New radial velocities from Anglo-Australian Telescope and PARAS observations during periastron passage greatly improve our knowledge of the eccentric nature of the orbit. The combined analysis of our Keplerian orbital and Hipparcos astrometry show that the inclination of the planetary orbit is > 1º.22, ruling out stellar masses for the companion. Our long-term robotic photometry show that the star is extremely stable over long timescales. Photometric monitoring of the star during predicted transit and periastron times using Microvariability and Oscillations of STars rule out a transit of the planet and reveal evidence of phase variations during periastron. These possible photometric phase variations may be caused by reflected light from the planet's atmosphere and the dramatic change in star–planet separation surrounding the periastron passage.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Kane, Stephen R.0000-0002-7084-0529
Wittenmyer, Robert A.0000-0001-9957-9304
Hinkel, Natalie R.0000-0003-0595-5132
Roy, Arpita0000-0001-8127-5775
Mahadevan, Suvrath0000-0001-9596-7983
Dragomir, Diana0000-0003-2313-467X
Matthews, Jaymie M.0000-0002-4461-080X
Henry, Gregory W.0000-0003-4155-8513
Chakraborty, Abhijit0000-0002-3815-8407
Boyajian, Tabetha S.0000-0001-9879-9313
Wright, Jason T.0000-0001-6160-5888
Ciardi, David R.0000-0002-5741-3047
Fischer, Debra A.0000-0003-2221-0861
Tinney, C. G.0000-0002-7595-0970
Additional Information:© 2016 The American Astronomical Society. Received 2015 November 27; accepted 2016 February 26; published 2016 April 11. TThe authors thank the anonymous referee, whose comments greatly improved the quality of the paper. S.R.K. and N.R.H. acknowledge financial support from the National Science Foundation through grant AST-1109662. G.W.H. acknowledges long-term support from Tennessee State University and the State of Tennessee through its Centers of Excellence program. H.R.A.J. acknowledges support from STFC via grants ST/M001008/1 and Leverhulme Trust RPG-2014-281. The authors thank the Gurushikar, Mount Abu Observatory staff and the PARAS technical staff for the observations with PARAS. The PARAS program is supported completely by the Physical Research Laboratory, Department of Space, Government of India. The results reported herein benefited from collaborations and/or information exchanged within NASA's Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA's Science Mission Directorate.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)ST/M001008/1
Leverhulme TrustRPG-2014-281
Department of Space (India)UNSPECIFIED
Tennessee State UniversityUNSPECIFIED
State of Tennessee Centers of Excellence programUNSPECIFIED
Subject Keywords:planetary systems; stars: individual (HD 20782) ; techniques: photometric; techniques: radial velocities
Issue or Number:1
Record Number:CaltechAUTHORS:20160509-135758149
Persistent URL:
Official Citation:Stephen R. Kane et al 2016 ApJ 821 65
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:66780
Deposited By: Ruth Sustaita
Deposited On:09 May 2016 22:49
Last Modified:13 Dec 2019 03:39

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