• DOI:10.3847/1538-3881/aa674a
• Corpus ID: 119491990

HAT-P-67b: An Extremely Low Density Saturn Transiting an F-subgiant Confirmed via Doppler Tomography

@article{Zhou2017HATP67bAE,
  title={HAT-P-67b: An Extremely Low Density Saturn Transiting an F-subgiant Confirmed via Doppler Tomography},
  author={G. Zhou and G'asp'ar 'A. Bakos and Joel D. Hartman and David W. Latham and Guillermo Torres and W. Bhatti and Kaloyan Penev and Lars A. Buchhave and G. Kov'acs and Allyson Bieryla and Samuel N. Quinn and Howard T. Isaacson and Benjamin J. Fulton and Emilio E. Falco and Zolt{\'a}n Csubry and Mark E. Everett and Tamas Szklenar and Gilbert A. Esquerdo and Perry L. Berlind and M. Calkins and Bence B'eky and Russell P. Knox and Phillip M. Hinz and Elliott P. Horch and Lea A. Hirsch and Steve B. Howell and Robert W. Noyes and Geoffrey W. Marcy and Miguel de Val-Borro and J'ozsef L'az'ar and Istv{\'a}n Papp and P'al S'ari},
  journal={The Astronomical Journal},
  year={2017},
  volume={153},
  pages={211}
}

• G. Zhou, G. Bakos, +29 authors P. S'ari
• Published 31 January 2017
• Physics, Geology
• The Astronomical Journal

We report the discovery of HAT-P-67b, which is a hot-Saturn transiting a rapidly rotating F-subgiant. HAT-P-67b has a radius of R_p = 2.085^(+0.096)_(-0.071) R_J, and orbites a M* = 1.642^(+0.155)_(-0.072) M⊙, R* = 2.546^(+0.099)_(-0.084) R⊙ host star in a ~4.81 day period orbit. We place an upper limit on the mass of the planet via radial velocity measurements to be M_p 0.056 M_J by limitations on Roche lobe overflow. Despite being a subgiant, the host star still exhibits relatively rapid rotation, with a projected rotational velocity of ν sin I⋆ = 35.8 ± 1.1 km s^(-1), which makes it difficult to precisely determine the mass of the planet using radial velocities. We validated HAT-P-67b via two Doppler tomographic detections of the planetary transit, which eliminate potential eclipsing binary blend scenarios. The Doppler tomographic observations also confirm that HAT-P-67b has an orbit that is aligned to within 12°, in projection, with the spin of its host star. HAT-P-67b receives strong UV irradiation and is among one of the lowest density planets known, which makes it a good candidate for future UV transit observations in the search for an extended hydrogen exosphere.