TOI-216b and TOI-216 c: two warm, large exoplanets in or slightly wide of the 2:1 orbital resonance

Rebekah I. Dawson, Chelsea X. Huang, Jack J. Lissauer, Karen A. Collins, Lizhou Sha, James Armstrong, Dennis M. Conti, Kevin I. Collins, Phil Evans, Tianjun Gan, Keith Horne, Michael Ireland, Felipe Murgas, Gordon Myers, Howard M. Relles, Ramotholo Sefako, Avi Shporer, Chris Stockdale, Marusa Zerjal, George ZhouG. Ricker, R. Vanderspek, David W. Latham, S. Seager, J. Winn, Jon M. Jenkins, L. G. Bouma, Douglas A. Caldwell, Tansu Daylan, John P. Doty, Scott Dynes, Gilbert A. Esquerdo, Mark Rose, Jeffrey C. Smith, Liang Yu

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


Warm, large exoplanets with 10–100 day orbital periods pose a major challenge to our understanding of how planetary systems form and evolve. Although high eccentricity tidal migration has been invoked to explain their proximity to their host stars, a handful reside in or near orbital resonance with nearby planets, suggesting a gentler history of in situ formation or disk migration. Here we confirm and characterize a pair of warm, large exoplanets discovered by the TESS Mission orbiting K-dwarf TOI-216. Our analysis includes additional transits and transit exclusion windows observed via ground-based follow-up. We find two families of solutions, one corresponding to a sub-Saturn-mass planet accompanied by a Neptune-mass planet and the other to a Jupiter in resonance with a sub-Saturn-mass planet. We prefer the second solution based on the orbital period ratio, the planet radii, the lower free eccentricities, and libration of the 2:1 resonant argument, but cannot rule out the first. The free eccentricities and mutual inclination are compatible with stirring by other, undetected planets in the system, particularly for the second solution. We discuss prospects for better constraints on the planets' properties and orbits through follow-up, including transits observed from the ground.
Original languageEnglish
Article number65
JournalAstronomical Journal
Issue number2
Publication statusPublished - 17 Jul 2019


  • Planets and satellites: detection
  • Planets and satellites: dynamical evolution and stability


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