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The Origin of Systems of Tightly Packed Inner Planets with Misaligned, Ultra-short-period Companions

Becker, J. and Batygin, K. and Fabrycky, D. and Adams, F. C. and Li, G. and Vanderburg, A. and Rodriguez, J. E. (2020) The Origin of Systems of Tightly Packed Inner Planets with Misaligned, Ultra-short-period Companions. Astronomical Journal, 160 (6). Art. No. 254. ISSN 1538-3881. doi:10.3847/1538-3881/abbad3.

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Ultra-short-period planets provide a window into the inner edge of the parameter space occupied by planetary orbits. In one particularly intriguing class of multiplanet systems, the ultra-short-period planet is flanked by short-period companions, and the outer planets occupy a discernibly distinct dynamical state. In the observational database, this phenomenon is represented by a small number of stars hosting systems of tightly packed coplanar planets as well as an ultra-short-period planet, whose orbit is misaligned relative to the mutual plane of the former. In this work, we explore two different mechanisms that can produce an ultra-short-period planet that is misaligned with the rest of its compact planetary system: natural decoupling between the inner and outer system via the stellar quadrupole moment, and decoupling forced by an external companion with finely tuned orbital parameters. These two processes operate with different timescales, and can thus occur simultaneously. In this work, we use the K2-266 system as an illustrative example to elucidate the dynamics of these two processes, and highlight the types of constraints that may arise regarding the dynamical histories of systems hosting ultra-short-period planets.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Becker, J.0000-0002-7733-4522
Batygin, K.0000-0002-7094-7908
Fabrycky, D.0000-0003-3750-0183
Adams, F. C.0000-0002-8167-1767
Li, G.0000-0001-8308-0808
Vanderburg, A.0000-0001-7246-5438
Rodriguez, J. E.0000-0001-8812-0565
Additional Information:© 2020 The American Astronomical Society. Received 2020 June 2; revised 2020 September 8; accepted 2020 September 21; published 2020 November 10. We thank Stephanie Douglas for useful conversations and Sean Matt for sharing what we needed from his models (Matt et al. 2015) in a convenient format. We thank Lynne Hillenbrand for useful conversations. J.C.B. is supported by the Heising-Simons 51 Pegasi b postdoctoral fellowship. D.F. acknowledges support from NASA's Exoplanet Research Program via grant NASA-NNX17AB93G. A.V.'s work was performed under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. We also thank the NASA Exoplanet Science Institute for hosting the 2018 Sagan Exoplanet Summer Workshop, at which this project originated. Software: pandas (McKinney 2010), IPython (Pérez & Granger 2007), matplotlib (Hunter 2007), scipy (Jones et al. 2001), numpy (Oliphant 2006), Jupyter (Kluyver et al. 2016), Mercury6 (Chambers 1999).
Funding AgencyGrant Number
Heising-Simons Foundation51 Pegasi b Fellowship
Subject Keywords:Exoplanet dynamics ; Exoplanet evolution
Issue or Number:6
Classification Code:Unified Astronomy Thesaurus concepts: Exoplanet dynamics (490); Exoplanet evolution (491)
Record Number:CaltechAUTHORS:20201019-082637052
Persistent URL:
Official Citation:J. Becker et al 2020 AJ 160 254
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:106135
Deposited By: Tony Diaz
Deposited On:20 Oct 2020 18:03
Last Modified:16 Nov 2021 18:50

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