2026ApJ...998..141Z

We present analyses of a nitrogen-enriched star-forming galaxy, ID60001, at z = 4.6928 based on James Webb Space Telescope/NIRSpec Multi-Object Spectroscopy and NIRCam photometry. From rest-frame optical emission lines we derive the nitrogen-to-oxygen (N/O) abundance ratio of ID60001 to be ${\mathrm{log}}({\rm{N}}/{\rm{O}})=-0.7{6}_{-0.03}^{+0.03}$ ($[{\rm{N}}/{\rm{O}}]=0.1{0}_{-0.03}^{+0.03}$), which is significantly elevated at the corresponding metallicity $12+{\mathrm{log}}({\rm{O}}/{\rm{H}})=7.7{5}_{-0.01}^{+0.01}$ (Z/Z_⊙ = 0.12) compared to local counterparts. We discuss possible scenarios for elevated N/O abundance in ID60001, including pristine gas inflow, Wolf-Rayet (W-R) stars, and oxygen depletion by Type II supernova winds. Based on the moderately broadened He IIλ4686 emission line, galaxy morphology, and star formation history, we conclude that the elevated N/O abundance of ID60001 is likely originated from massive (>25 M_⊙) W-R stars that directly collapse into a black hole. We also stress the importance of reliable electron density measurements when deriving N/O abundance with rest-frame optical emission lines.