Spin-orbit alignment for KELT-7b and HAT-P-56b via Doppler tomography with TRES

George Zhou, David W. Latham, Allyson Bieryla, Thomas G. Beatty, Lars A. Buchhave, Gilbert A. Esquerdo, Perry Berlind, Michael L. Calkins

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


We present Doppler tomographic analyses for the spectroscopic transits of KELT-7b and HAT-P-56b, two hot-Jupiters orbiting rapidly rotating F-dwarf host stars. These include analyses of archival Tillinghast Reflector Echelle Spectrograph (TRES) observations for KELT-7b, and a new TRES transit observation of HAT-P-56b. We report spin-orbit aligned geometries for KELT-7b (2.°7 ± 0.°6) and HAT-P-56b (8° ± 2°). The host stars KELT-7 and HAT-P-56 are among some of the most rapidly rotating planet-hosting stars known. We examine the tidal re-alignment model for the evolution of the spin-orbit angle in the context of the spin rates of these stars. We find no evidence that the rotation rates of KELT-7 and HAT-P-56 have been modified by star-planet tidal interactions, suggesting that the spin-orbit angle of systems around these hot stars may represent their primordial configuration. In fact, KELT-7 and HAT-P-56 are two of three systems in supersynchronous, spin-orbit aligned states, where the rotation periods of the host stars are faster than the orbital periods of the planets.

Original languageEnglish (US)
Pages (from-to)3376-3383
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
StatePublished - Aug 11 2016
Externally publishedYes


  • Planetary systems
  • Planets and satellites: individual: (KELT-7b, HAT-P-56b)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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