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A General Origin for Multiplanetary Systems With Significantly Misaligned USP Planets

Brefka, L. and Becker, J. C. (2021) A General Origin for Multiplanetary Systems With Significantly Misaligned USP Planets. Astronomical Journal, 162 (6). Art. No. 242. ISSN 0004-6256. doi:10.3847/1538-3881/ac2a32.

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Ultra-short-period (USP) planets are exoplanets that have orbital periods of less than one day and are unique because they orbit inside the nominal magnetic truncation gap of their host stars. In some cases, USP planets have also been observed to exhibit unique dynamical parameters such as significant misalignments in inclination angle with respect to nearby planets. In this paper, we explore how the geometry of a multiplanet system hosting a USP planet can be expected to evolve as a star ages. In particular, we explore the relationship between the mutual inclination of the USP planet and the quadrupole moment (J2) of the host star. We use secular perturbation theory to predict the past evolution of the example TOI-125 system, and then confirm the validity of our results using long-term N-body simulations. Through investigating how the misalignment between the candidate USP planet and the three other short-period planets in the TOI-125 system arose, we intend to derive a better understanding of the population of systems with misaligned USP planets and how their observed parameters can be explained in the context of their dynamical histories.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Brefka, L.0000-0001-9256-5508
Becker, J. C.0000-0002-7733-4522
Alternate Title:A General Origin for Multi-Planetary Systems With Significantly Misaligned USP Planets
Additional Information:© 2021. The American Astronomical Society. Received 2021 July 7; revised 2021 September 15; accepted 2021 September 23; published 2021 November 16. We would like to thank Thea Faridani for useful conversations, and Konstantin Batygin for guidance and advice. J.C.B. has been supported by the Heising-Simons 51 Pegasi b postdoctoral fellowship. L.B. also thanks the Heising-Simons foundation for financial support. We would also like to thank the UROP / Research Scholars program at the University of Michigan for providing this research opportunity and for the continued support throughout these difficult times. We would like to thank the anonymous referee for useful comments that improved the manuscript. Software: pandas (McKinney 2010), IPython (Pérez & Granger 2007), matplotlib (Hunter 2007), scipy (Jones et al. 2001), numpy (Oliphant 2006), Jupyter (Kluyver et al. 2016), Rebound (Rein 2012), Reboundx (Tamayo et al. 2020).
Funding AgencyGrant Number
Heising-Simons Foundation51 Pegasi b Fellowship
University of MichiganUNSPECIFIED
Subject Keywords:Exoplanet dynamics; Exoplanet systems; Exoplanet astronomy
Issue or Number:6
Classification Code:Unified Astronomy Thesaurus concepts: Exoplanet dynamics (490); Exoplanet systems (484); Exoplanet astronomy (486)
Record Number:CaltechAUTHORS:20211123-232759151
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Official Citation:L. Brefka and J. C. Becker 2021 AJ 162 242
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:112024
Deposited By: Tony Diaz
Deposited On:24 Nov 2021 20:31
Last Modified:24 Nov 2021 20:31

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