ξ_2.5 vs. initial mass for models with varying initial rotational velocities V_ini and metallicities. The left, middle, and right panels correspond to models with V_ini = 0, 300 km s⁻¹, and 600 km s⁻¹, respectively. Metallicities of Z_⊙, 1/10 Z_⊙, and 1/50 Z_⊙are represented in red, green and black, respectively. The squares mark the occurrence of CHE. The left and middle blue triangles indicate model calculations from Li et al. (2023) (Z = 0.0017), and the right blue triangle denotes the rapidly rotating model from Aguilera-Dena et al. (2020) (1/50 Z_⊙). The dashed lines mark explosion criteria for ξ_2.5: the black line shows O’Connor & Ott (2011), and others from our results.