A Caltech Library Service

Kepler-1656b: A Dense Sub-Saturn with an Extreme Eccentricity

Brady, Madison T. and Petigura, Erik A. and Knutson, Heather A. and Sinukoff, Evan and Isaacson, Howard and Hirsch, Lea A. and Fulton, Benjamin J. and Kosiarek, Molly R. and Howard, Andrew W. (2018) Kepler-1656b: A Dense Sub-Saturn with an Extreme Eccentricity. Astronomical Journal, 156 (4). Art. No. 147. ISSN 1538-3881.

[img] PDF - Published Version
See Usage Policy.

[img] PDF - Accepted Version
See Usage Policy.


Use this Persistent URL to link to this item:


Kepler-1656b is a 5 R⊕ planet with an orbital period of 32 days initially detected by the prime Keplermission. We obtained precision radial velocities of Kepler-1656 with Keck/HIRES in order to confirm the planet and to characterize its mass and orbital eccentricity. With a mass of 48 ± 4 M⊕, Kepler-1656b is more massive than most planets of comparable size. Its high mass implies that a significant fraction, roughly 80%, of the planet's total mass is in high-density material such as rock/iron, with the remaining mass in a low-density H/He envelope. The planet also has a high eccentricity of 0.84 ± 0.01, the largest measured eccentricity for any planet less than 100 M⊕. The planet's high density and high eccentricity may be the result of one or more scattering and merger events during or after the dispersal of the protoplanetary disk.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Petigura, Erik A.0000-0003-0967-2893
Knutson, Heather A.0000-0002-0822-3095
Sinukoff, Evan0000-0002-5658-0601
Isaacson, Howard0000-0002-0531-1073
Hirsch, Lea A.0000-0001-8058-7443
Fulton, Benjamin J.0000-0003-3504-5316
Kosiarek, Molly R.0000-0002-6115-4359
Howard, Andrew W.0000-0001-8638-0320
Additional Information:© 2018 The American Astronomical Society. Received 2018 June 26; revised 2018 July 27; accepted 2018 July 29; published 2018 September 10. We thank Konstantin Batygin for useful discussions, as well as Lauren Weiss and Ian Crossfield for their assistance with Keck/HIRES observations. M.T.B. acknowledges support from a Summer Undergraduate Research Fellowship (SURF) at Caltech, which was funded with the assistance of Hannah Bradley. E.A.P. acknowledges support from a Hubble Fellowship grant HST-HF2-51365.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. for NASA under contract NAS 5-26555. 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. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has long had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Software: Astropy (Astropy Collaboration et al. 2013), batman (Kreidberg 2015), emcee (Foreman-Mackey et al. 2013), Numpy/Scipy (Van Der Walt et al. 2011), Matplotlib (Hunter 2007), Pandas (McKinney 2010), RadVel (Fulton et al. 2018).
Group:Astronomy Department
Funding AgencyGrant Number
Caltech Summer Undergraduate Research Fellowship (SURF)UNSPECIFIED
NASA Hubble FellowshipHST-HF2-51365.001-A
NASANAS 5-26555
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:planets and satellites: detection – planets and satellites: dynamical evolution and stability – planets and satellites: formation – planets and satellites: individual (Kepler-1656) – techniques: photometric – techniques: radial velocities
Issue or Number:4
Record Number:CaltechAUTHORS:20180910-092840714
Persistent URL:
Official Citation:Madison T. Brady et al 2018 AJ 156 147
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:89480
Deposited By: Tony Diaz
Deposited On:10 Sep 2018 16:52
Last Modified:03 Oct 2019 20:16

Repository Staff Only: item control page