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Journal Articles The Astronomical Journal Year : 2020

XO-7 b: A Transiting Hot Jupiter with a Massive Companion on a Wide Orbit

Nicolas Crouzet
Brian F. Healy
  • Function : Author
Guillaume Hébrard
P. R. Mccullough
  • Function : Author
Doug Long
  • Function : Author
Pilar Montañés-Rodríguez
  • Function : Author
Ignasi Ribas
Francesc Vilardell
  • Function : Author
Enrique Herrero
  • Function : Author
Enrique Garcia-Melendo
  • Function : Author
Jerry Foote
  • Function : Author
Joe Garlitz
  • Function : Author
Phillip Vo
  • Function : Author
Nuno C. Santos
  • Function : Author
Jos de Bruijne
  • Function : Author
Louise D. Nielsen
  • Function : Author


Transiting planets orbiting bright stars are the most favorable targets for follow-up and characterization. We report the discovery of the transiting hot Jupiter XO-7 b and of a second, massive companion on a wide orbit around a circumpolar, bright, and metal-rich G0 dwarf (V = 10.52, {T}eff}=6250+/- 100 {{K}}, [{Fe}/{{H}}]=0.432+/- 0.057 {dex}). We conducted photometric and radial velocity follow-up with a team of amateur and professional astronomers. XO-7 b has a period of 2.8641424+/- 0.0000043 days, a mass of 0.709+/- 0.034 {M}{{J}}, a radius of 1.373+/- 0.026 {R}{{J}}, a density of 0.340+/- 0.027 {{g}} {cm}}-3, and an equilibrium temperature of 1743+/- 23 {{K}}. Its large atmospheric scale height and the brightness of the host star make it well suited to atmospheric characterization. The wide-orbit companion is detected as a linear trend in radial velocities with an amplitude of ∼ 100 {{m}} {{{s}}}-1 over two years, yielding a minimum mass of 4 {M}{{J}}; it could be a planet, a brown dwarf, or a low-mass star. The hot Jupiter orbital parameters and the presence of the wide-orbit companion point toward a high-eccentricity migration for the hot Jupiter. Overall, this system will be valuable to understand the atmospheric properties and migration mechanisms of hot Jupiters and will help constrain the formation and evolution models of gas giant exoplanets.

Dates and versions

insu-03667137 , version 1 (13-05-2022)



Nicolas Crouzet, Brian F. Healy, Guillaume Hébrard, P. R. Mccullough, Doug Long, et al.. XO-7 b: A Transiting Hot Jupiter with a Massive Companion on a Wide Orbit. The Astronomical Journal, 2020, 159, ⟨10.3847/1538-3881/ab5b12⟩. ⟨insu-03667137⟩
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