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. The Astrophysical Journal, 821 (1). ISSN 0004-637X

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Abstract

Planets in highly eccentric orbits form a class of objects not seen within our Solar System. The most extreme case known amongst 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 (TERMS). We obtained CHIRON spectra to perform an independent estimation of the fundamental stellar parameters. New radial velocities from AAT and PARAS observations during periastron passage greatly improve the 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 > 1.25 degrees, 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 MOST rule out a transit of the planet and reveal evidence of phase variations during periastron. These possible photometric phase variations are likely caused by reflected light from the planet's atmosphere and the dramatic change in star--planet separation surrounding the periastron passage.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Published version made accessible, in accordance with the copyright policy of the publisher.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Agricultural, Computational and Environmental Sciences
Date Deposited: 15 Apr 2016 03:17
Last Modified: 06 Apr 2017 06:43
Uncontrolled Keywords: planetary systems – techniques, photometric – techniques, radial velocities – stars, individual (HD 20782)
Fields of Research : 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Identification Number or DOI: 10.3847/0004-637X/821/1/65
URI: http://eprints.usq.edu.au/id/eprint/28510

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