We explore the wind-driving mechanism of giant stars through the nearby ( 117 pc ) , intermediate-luminosity ( L \approx 1600 L _ { \odot } ) star EU Del ( HIP 101810 , HD 196610 ) .
APEX observations of the CO ( 3–2 ) and ( 2–1 ) transitions are used to derive a wind velocity of 9.51 \pm 0.02 km s ^ { -1 } , a ^ { 12 } C/ ^ { 13 } C ratio of 14 ^ { +9 } _ { -4 } , and a mass-loss rate of a few \times 10 ^ { -8 } M _ { \odot } yr ^ { -1 } .
From published spectra , we estimate that the star has a metallicity of [ Fe/H ] = –0.27 \pm \sim 0.30 dex .
The star ’ s dusty envelope lacks a clear 10- \mu m silicate feature , despite the star ’ s oxygen-rich nature .
Radiative transfer modelling can not fit a wind acceleration model which relies solely on radiation pressure on condensing dust .
We compare our results to VY Leo ( HIP 53449 ) , a star with similar temperature and luminosity , but different pulsation properties .
We suggest the much stronger mass loss from EU Del may be driven by long-period stellar pulsations , due to its potentially lower mass .
We explore the implications for the mass-loss rate and wind velocities of other stars .