Radial profiles of percentage contributions of the dominant oxygen-bearing molecules to the total elemental oxygen abundance (=3.2 × 10⁻⁴) in the NGC 1333-IRAS 2A envelope model (left panels) and the NGC 1333-IRAS 4A envelope model (right panels). The top, middle, and bottom panels show the radial profiles with L_X = 10²⁸, 10³⁰, and 10³² erg s⁻¹, respectively. The red, blue, purple, black, and green line profiles respectively show the contribution of CO, H₂O, O, O₂, and CO₂ molecules. The solid and dashed line profiles show the contribution of gaseous and icy molecules. Since O₂ and CO₂ include two oxygen atoms per molecule, the percentage contributions are twice as high as those of CO, H₂O, and O whenthey have same fractional abundances with respect to hydrogen nuclei.