  Non-gravitationally induced condensations are observed in many astrophysical
environments. Such structures are formed due to energy loss by optically thin
radiative emission. Instead of solving the full radiative transfer equations,
precomputed cooling curves are typically used in numerical simulations. In the
literature, there exists a wide variety of cooling curves and they are quite
often used as unquestionable ingredients. We determine the effect of the
optically thin cooling curves on the formation and evolution of condensations.
We perform a case study using thermal instability as a mechanism to form in
situ condensations. We compare 2D numerical simulations with different cooling
curves using interacting slow magnetohydrodynamic (MHD) waves as trigger for
the thermal instability. Furthermore, we discuss a bootstrap measure to
investigate the far non-linear regime of thermal instability. In the appendix,
we include the details of all cooling curves implemented in MPI-AMRVAC and
briefly discuss a hydrodynamic variant of the slow MHD waves setup for thermal
instability. For all tested cooling curves, condensations are formed. However,
the growth rates of the thermal instability are different. Also, the morphology
of the formed condensation widely varies. We find fragmentation that is
affected by the low-temperature treatment of the cooling curves. Condensations
formed using cooling curves that vanish for temperatures lower than 20 000 K
seem to be more stable against dynamical instabilities. The non-linear regime
and fragmentation in the hydrodynamic case differ greatly from the MHD case. We
advocate the use of modern cooling curves, based on accurate computations and
up-to-date atomic parameters and solar abundances. Our bootstrap procedure can
be used in future multi-dimensional simulations, to study fine-structure
dynamics in solar prominences.
