  Astrophysical objects frequently exhibit some irregularities or complex
behaviour in their light curves. We focus primarily on hot stars, where both
radial and non-radial pulsations are observed. One of the primary research
goals is to determine physical parameters of stellar pulsations by analyzing
their light curves or spectra, focusing on periodic or quasiperiodic behaviour.
  We analyse the feasibility of classical methods for period searches in a
nonlinear chaotic system, such as the R\"ossler system, where a period does not
exist at all. As an astrophysical application of the chaotic system, we utilize
a simple model of stellar pulsation with two different sets of parameters
corresponding to periodic and chaotic behaviour. For both models we create a
synthetic signal, and then apply widely used methods for period finding, such
as the phase dispersion method and periodograms. For comparison, a
quasi-periodic signal is employed as well.
  The period analysis indicates periods even for the chaotic signal. Such
periods are apparently spurious. This implies that it is very problematic to
distinguish chaotic and quasiperiodic process by such an analysis only.
