Stability of kink defects in a deformed O(3) linear sigma model

We identify the kinks of a deformed O(3) linear sigma model as the solutions of a set of first-order systems of equations; the above model is a generalization of the MSTB model with a three-component scalar field. Taking into account certain kink energy sum rules we show that the variety of kinks has the structure of a moduli space that can be compactified in a fairly natural way. The generic kinks, however, are unstable and Morse theory provides the framework for the analysis of kink stability.