On the absence of symbiotic stars in globular clusters
  Even though plenty of symbiotic stars (SySts) have been found in the Galactic
field and nearby galaxies, not a single one has ever been confirmed in a
Galactic globular cluster (GC). We investigate the lack of such systems in GCs
for the first time by analysing 144 GC models evolved with the MOCCA code,
which have different initial properties and are roughly representative of the
Galactic GC population. We focus here on SySts formed through the
wind-accretion channel, which can be consistently modelled in binary population
synthesis codes. We found that the orbital periods of the majority of such
SySts are sufficiently long (${\gtrsim10^3}$ d) so that, for very dense GC
models, dynamical interactions play an important role in destroying their
progenitors before the present day (${\sim11-12}$ Gyr). In less dense GC
models, some SySts are still predicted to exist. However, these systems tend to
be located far from the central parts (${\gtrsim70}$ per cent are far beyond
the half-light radius) and are sufficiently rare (${\lesssim1}$ per GC per
Myr), which makes their identification rather difficult in observational
campaigns. We propose that future searches for SySts in GCs should be performed
in the outskirts of nearby low-density GCs with sufficiently long half-mass
relaxation times and relatively large Galactocentric distances. Finally, we
obtained spectra of the candidate proposed in $\omega$ Cen (SOPS IV e-94) and
showed that this object is most likely not a SySt.
