The Gum 31 nebula is part of the Carina nebula complex and is located at the northwestern periphery. Inside of the nebula is the young (2-3 Myr) cluster NGC 3324.
The most massive stars of the cluster, HD92206, a system with 3 O-type stars, and the A0 supergiant HD92207 at the southern border provide the energy for the red glow.