Possible solution to the riddle of HD 82943 multi-planet system: the three-planet resonance 1:2:5?

Roman V. Baluev, Cristian Beauge (Submitted on 26 Oct 2013) 

We carry out a new analysis of the published radial velocity data for the planet-hosting star HD82943. We include the recent Keck/HIRES measurements as well as the aged but much more numerous CORALIE data. We find that the CORALIE radial velocity measurements are polluted by a systematic annual variation which affected the robustness of many previous results. We show that after purging this variation, the residuals still contain a clear signature of an additional 1100 days periodicity. The latter variation leaves significant hints in all three independent radial velocity subsets that we analysed: the CORALIE data, the Keck data acquired prior to a hardware upgrade, and the Keck data taken after the upgrade.

We mainly treat this variation as a signature of a third planet in the system, although we cannot rule out other interpretations, such as long-term stellar activity. We find it easy to naturally obtain a stable three-planet radial-velocity fit close to the three-planet mean-motion resonance 1:2:5, with the two main planets (those in the 1:2 resonance) in an aligned apsidal corotation. The dynamical status of the third planet is still uncertain: it may reside in as well as slightly out of the 5:2 resonance. We obtain the value of 1075 days for its orbital period and of 0.3 M Jup for its minimum mass, while the eccentric parameters are uncertain.

Comments: 15 pages, 5 tables, 14 figures; submitted to MNRAS

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Cite as: arXiv:1310.7101 [astro-ph.EP]

(or arXiv:1310.7101v1 [astro-ph.EP] for this version)

Submission history From: Roman Baluev [v1] Sat, 26 Oct 2013 11:22:35 GMT (2636kb)