  We report the detection of the Rossiter-McLaughlin effect for the eccentric,
super-Neptune exoplanet HAT-P-11b, based on radial velocity measurements taken
with HDS mounted on the Subaru 8.2m telescope, and simultaneous photometry with
the FTN 2.0m telescope, both located in Hawai'i. The observed radial velocities
during a planetary transit of HAT-P-11b show a persistent blue-shift,
suggesting a spin-orbit misalignment in the system. The best-fit value for the
projected spin-orbit misalignment angle is $\lambda= 103_{-19}^{+23}$ deg. Our
result supports the notion that eccentric exoplanetary systems are likely to
have significant spin-orbit misalignment (e.g., HD 80606, WASP-8, WASP-14,
WASP-17, and XO-3). This fact suggests that not only hot-Jupiters but also
super-Neptunes like HAT-P-11b had once experienced dynamical processes such as
planet-planet scattering or the Kozai migration.
