Simulations of stellar radial-velocity and spectral line bisector variations .1. Nonradial pulsations

The radial-velocity and spectral variations are calculated for low-amplitude nonradial pulsations in slowly rotating stars (v sin i=3 km s(-1)). Sectoral modes (l=-m) in the range l=1-8 are considered. An empirical equation relating the pulsational amplitude to the ''observed'' stellar radial-velocity amplitude is derived and this indicates that precise radial-velocity techniques should be able to detect low-amplitude (<1 km s(-1)) pulsations for sectoral modes as high as l=6. The spectral variations manifest themselves via changes in the span and curvature of the line bisector which are maximized for m=4. These spectral variations can be used to distinguish between radial-velocity variations due to pulsations from those due to the reflex motion of the star caused by the presence of a low-mass companion. However, these measurements require data taken at high resolution (lambda/Delta lambda>100,000) and high signal-to-noise ratios (S/N>500).