Detection of a Third Planet in the HD 74156 System Using the Hobby-Eberly Telescope
arXiv:0709.1656 · doi:10.1086/523701
Abstract
We report the discovery of a third planetary mass companion to the G0 star HD 74156. High precision radial velocity measurements made with the Hobby-Eberly Telescope aided the detection of this object. The best fit triple Keplerian model to all the available velocity data yields an orbital period of 347 days and minimum mass of 0.4 M_Jup for the new planet. We determine revised orbital periods of 51.7 and 2477 days, and minimum masses of 1.9 and 8.0 M_Jup respectively for the previously known planets. Preliminary calculations indicate that the derived orbits are stable, although all three planets have significant orbital eccentricities (e = 0.64, 0.43, and 0.25). With our detection, HD 74156 becomes the eighth normal star known to host three or more planets. Further study of this system's dynamical characteristics will likely give important insight to planet formation and evolutionary processes.
24 pages, 4 tables, 6 figures. Accepted for publication in ApJ. V2 fixed table 4 page overrun. V3 added references
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- Accounting for velocity jitter in planet search surveys
- A Search for Multi-Planet Systems Using the Hobby-Eberly Telescope
- A secular theory of coplanar, non-resonant planetary system
- A dynamical perspective on additional planets in 55 Cancri
- Two Jupiter-Mass Planets Orbiting HD 154672 and HD 205739
- Stability of additional planets in and around the habitable zone of the HD 47186 Planetary System