• DOI:10.1051/0004-6361/200912700
• Corpus ID: 119183917

The HARPS search for southern extra-solar planets - XIX. Characterization and dynamics of the GJ 876 planetary system

@article{Correia2010TheHS,
  title={The HARPS search for southern extra-solar planets - XIX. Characterization and dynamics of the GJ 876 planetary system},
  author={Alexandre C. M. Correia and Jocelyn Couetdic and Jacques Laskar and Xavier Bonfils and Michel Mayor and J L Bertaux and François Bouchy and Xavier Delfosse and Thierry Forveille and Cristophe Lovis and Francesco A. Pepe and Christian Perrier and Didier Queloz and St{\'e}phane Udry},
  journal={Astronomy and Astrophysics},
  year={2010},
  volume={511}
}

• A. Correia, J. Couetdic, +11 authors S. Udry
• Published 26 January 2010
• Physics, Geology
• Astronomy and Astrophysics

Precise radial-velocity measurements for data acquired with the HARPS spectrograph infer that three planets orbit the M4 dwarf star GJ876. In particular, we confirm the existence of planet d, which orbits every 1.93785 days. We find that its orbit may have significant eccentricity (e = 0.14), and deduce a more accurate estimate of its minimum mass of 6.3 M⊕. Dynamical modeling of the HARPS measurements combined with literature velocities from the Keck Observatory strongly constrain the orbital inclinations of the b and c planets. We find that ib = 48.9 ◦ ± 1.0 ◦ and ic = 48.1 ◦ ± 2.1 ◦ , which infers the true planet masses of Mb = 2.64 ± 0.04 MJup and Mc = 0.83 ± 0.03 MJup, respectively. Radial velocities alone, in this favorable case, can therefore fully determine the orbital architecture of a multi-planet system, without the input from astrometry or transits. The orbits of the two giant planets are nearly coplanar, and their 2:1 mean motion resonance ensures stability over at least 5 Gyr. The libration amplitude is smaller than 2 ◦ , suggesting that it was damped by some dissipative process during planet formation. The system has space for a stable fourth planet in a 4:1 mean motion resonance with planet b, with a period around 15 days. The radial velocity measurements constrain the mass of this possible additional planet to be at most that of the Earth.