  We present evidence for a new two-planet system around the giant star
HD202696 (= HIP105056, BD+26 4118). The discovery is based on public HIRES
radial velocity measurements taken at Keck Observatory between July 2007 and
September 2014. We estimate a stellar mass of 1.91$^{+0.09}_{-0.14}M_\odot$ for
HD202696, which is located close to the base of the red giant branch. A
two-planet self-consistent dynamical modeling MCMC scheme of the radial
velocity data followed by a long-term stability test suggests planetary orbital
periods of $P_{\rm b}$ = 517.8$_{-3.9}^{+8.9}$ days and $P_{\rm c}$ =
946.6$_{-20.9}^{+20.7}$ days, eccentricities of $e_{\rm b}$ =
0.011$_{-0.011}^{+0.078}$ and $e_{\rm c}$ = 0.028$_{-0.012}^{+0.065}$ , and
minimum dynamical masses of $m_{\rm b}$ =
2.00$_{-0.10}^{+0.22}$\,$M_{\mathrm{Jup}}$ and $m_{\rm c}$ =
1.86$_{-0.23}^{+0.18}$,$M_{\mathrm{Jup}}$, respectively. Our stable MCMC
samples are consistent with orbital configurations predominantly in a mean
period ratio of 11:6 and its close-by high order mean-motion commensurabilities
with low eccentricities. For the majority of the stable configurations we find
an aligned or anti-aligned apsidal libration (i.e.\ $\Delta\omega$ librating
around 0$^\circ$ or 180$^\circ$), suggesting that the HD202696 system is likely
dominated by secular perturbations near the high-order 11:6 mean-motion
resonance. The HD202696 system is yet another Jovian mass pair around an
intermediate mass star with a period ratio below the 2:1 mean motion resonance.
Therefore, the HD202696 system is an important discovery, which may shed light
on the primordial disk-planet properties needed for giant planets to break the
strong 2:1 mean motion resonance and settle in more compact orbits.

Earth and Planetary Astrophysics