The Lick-Carnegie Survey: A New Two-Planet System Around the Star HD 207832

TL;DR

This paper reports the discovery of a two-planet system around star HD 207832 using radial velocity measurements, revealing planetary orbits, masses, and potential orbital stability zones, with no evidence of additional planets.

Contribution

First detection of a two-planet system around HD 207832 via precise radial velocities, including analysis of orbital parameters and stability considerations.

Findings

Two Jovian-mass planets with specific orbital periods and eccentricities.

Stability analysis shows limited regions for additional terrestrial planets.

No evidence found for other planets in the system.

Abstract

Keck/HIRES precision radial velocities of HD 207832 indicate the presence of two Jovian-type planetary companions in Keplerian orbits around this G star. The planets have minimum masses of 0.56 and 0.73 Jupiter-masses with orbital periods of ~162 and ~1156 days, and eccentricities of 0.13 and 0.27, respectively. Stromgren b and y photometry reveals a clear stellar rotation signature of the host star with a period of 17.8 days, well separated from the period of the radial velocity variations, reinforcing their Keplerian origin. The values of the semimajor axes of the planets suggest that these objects have migrated from the region of giant planet formation to closer orbits. In order to examine the possibility of the existence of additional (small) planets in the system, we studied the orbital stability of hypothetical terrestrial-sized objects in the region between the two planets and interior to the orbit of the inner body. Results indicated that stable orbits exist only in a small region interior to planet b. However, the current observational data offer no evidence for the existence of additional objects in this system.