  While Population III stars are typically thought to be massive, pathways
towards lower-mass Pop III stars may exist when the cooling of the gas is
particularly enhanced. A possible route is enhanced HD cooling during the
merging of dark-matter halos. The mergers can lead to a high ionization degree
catalysing the formation of HD molecules and may cool the gas down to the
cosmic microwave background (CMB) temperature. In this paper, we investigate
the merging of mini-halos with masses of a few 10$^5$ M$_\odot$ and explore the
feasibility of this scenario. We have performed three-dimensional cosmological
hydrodynamics calculations with the ENZO code, solving the thermal and chemical
evolution of the gas by employing the astrochemistry package KROME. Our results
show that the HD abundance is increased by two orders of magnitude compared to
the no-merging case and the halo cools down to $\sim$60 K triggering
fragmentation. Based on Jeans estimates the expected stellar masses are about
10 M$_\odot$. Our findings show that the merging scenario is a potential
pathway for the formation of low-mass stars.
