A Caltech Library Service

The Resilience of Kepler Systems to Stellar Obliquity

Spalding, Christopher and Marx, Noah W. and Batygin, Konstantin (2018) The Resilience of Kepler Systems to Stellar Obliquity. Astronomical Journal, 155 (4). Art. no. 167. ISSN 1538-3881. doi:10.3847/1538-3881/aab43a.

[img] PDF - Published Version
See Usage Policy.

[img] PDF - Accepted Version
See Usage Policy.


Use this Persistent URL to link to this item:


The Kepler mission and its successor K2 have brought forth a cascade of transiting planets. Many of these planetary systems exhibit multiple members, but a large fraction possess only a single transiting example. This overabundance of singles has led to the suggestion that up to half of Kepler systems might possess significant mutual inclinations between orbits, reducing the transiting number (the so-called "Kepler Dichotomy"). In a recent paper, Spalding & Batygin demonstrated that the quadrupole moment arising from a young, oblate star is capable of misaligning the constituent orbits of a close-in planetary system enough to reduce their transit number, provided that the stellar spin axis is sufficiently misaligned with respect to the planetary orbital plane. Moreover, tightly packed planetary systems were shown to be susceptible to becoming destabilized during this process. Here, we investigate the ubiquity of the stellar obliquity-driven instability within systems with a range of multiplicities. We find that most planetary systems analyzed, including those possessing only two planets, underwent instability for stellar spin periods below ~3 days and stellar tilts of order 30°. Moreover, we are able to place upper limits on the stellar obliquity in systems such as K2-38 (obliquity lesssim20°), where other methods of measuring the spin–orbit misalignment are not currently available. Given the known parameters of T-Tauri stars, we predict that up to one-half of super-Earth-mass systems may encounter the instability, in general agreement with the fraction typically proposed to explain the observed abundance of single-transiting systems.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Spalding, Christopher0000-0001-9052-3400
Batygin, Konstantin0000-0002-7094-7908
Additional Information:© 2018. The American Astronomical Society. Received 2018 February 5; revised 2018 February 26; accepted 2018 March 3; published 2018 March 23. This research is based in part on work supported by NSF grant AST 1517936 and the NESSF Graduate Fellowship in Earth and Planetary Sciences (CS). K.S. thanks the David and Lucile Packard Foundation for their generous support. Both authors are thankful for Caltech's SRC program that facilitated this investigation. We thank Erik Petigura, Josh Winn, Linda Khalaf, Jackie Lopez, and Greg Laughlin for insightful conversations and the referee, Juliette Becker, for an insightful report that led to substantial improvements in the manuscript.
Group:Astronomy Department
Funding AgencyGrant Number
NASA Earth and Space Science FellowshipUNSPECIFIED
David and Lucile Packard FoundationUNSPECIFIED
Subject Keywords:planet–star interactions; planets and satellites: dynamical evolution and stability; planets and satellites: formation
Issue or Number:4
Record Number:CaltechAUTHORS:20180328-133305944
Persistent URL:
Official Citation:Christopher Spalding et al 2018 AJ 155 167
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:85474
Deposited By: George Porter
Deposited On:28 Mar 2018 21:01
Last Modified:15 Nov 2021 20:29

Repository Staff Only: item control page