The total ejecta mass (black curve), He core mass (dark gray curve), and CO core mass (light gray curve) as a function of the ZAMS mass for the single-star CC models of Jacovich et al. (2021). The green curve represents the total mass of O, Ne, Mg, Si, S, and Fe inside the He core as a function of the ZAMS mass. All curves exclude the NS mass. The horizontal green band indicates the total X-ray-measured mass of O, Ne, Mg, Si, S, and Fe, including the uncertainties (Bhalerao et al. 2019). The gray vertical band marks the corresponding range of consistent ZAMS masses.