Understanding WASP-12b

Avery Bailey, Jeremy Goodman

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


The orbital period of the hot Jupiter WASP-12b is apparently changing. We study whether this reflects orbital decay due to tidal dissipation in the star, or apsidal precession of a slightly eccentric orbit. In the latter case, a third body or other perturbation would be needed to sustain the eccentricity against tidal dissipation in the planet itself. We have analysed several such perturbative scenarios, but none is satisfactory. Most likely, therefore, the orbit really is decaying. If this is due to a dynamical tide, then WASP-12 should be a subgiant without a convective core as previous studies have suggested. We have modelled the star with the MESA code. Satisfactory main-sequence models can be found if the effective temperature is at the upper end of reported estimates, but subgiant models are in greater tension with current observational constraints.

Original languageEnglish (US)
Pages (from-to)1872-1882
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
StatePublished - Jan 11 2019

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Planet-star interactions
  • Planets and satellites: dynamical evolution and stability
  • Planets and satellites: individual: WASP-12b
  • Stars: individual: WASP-12


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