Researchers have identified a new asymptotically flat toric gravitational instanton, which presents as a particular case of the Euclidean double Kerr-NUT solution. This finding represents the third member of an infinite sequence of asymptotically flat toric gravitational instantons, whose existence was previously demonstrated by Li and Sun. The first two instantons in this sequence are the Kerr instanton and the Chen-Teo instanton.

This new instanton is notable for being the first known example of a Ricci-flat gravitational instanton that is not Hermitian, opening new avenues in the understanding of these geometric structures in general relativity.