  We report the detection of multi-periodic oscillations of the cool evolved
star alpha Hya (HD 81797, K3II-III). Two-hundred and forty-three
high-resolution spectra (R=48,000) of this star have been obtained in March and
April 2005 with FEROS at the 2.2 m-MPG/ESO telescope in La Silla Observatory,
Chile. We observed oscillations in the stellar radial velocity and the
asymmetry of the spectral line profile. We detected oscillation frequencies of
the stellar radial velocity in two frequency regions, nu= 2-30 muHz and nu=
50-120 muHz. The corresponding periods are P= 0.6-5.6 days and P= 2.3-5.5
hours, respectively. In addition to these oscillations we also observed a trend
in the radial velocity which shows evidence for a long-term variability.
Furthermore, our measurements show a correlation between the variation in the
radial velocity and the asymmetry of the spectral line profile, as measured in
the bisector velocity spans. The line bisectors also show oscillations in the
same frequency regions as those of the radial velocity. We identified 13
oscillation frequencies in the bisector variation with equidistant separations
of 8.09 +- 0.32 muHz in the lower frequency region and 7.69 +- 0.47 muHz in the
higher frequency region. The source of the short-term oscillations of alpha Hya
is obviously due to non-radial stellar pulsations. These oscillations may have
a similar origin like oscillations in solar-like stars. The detection of the
multi-periodic oscillations in alpha-Hya makes this star to be an amenable
target for asteroseismology, in particular, as it is a star in the red giant
branch.
