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We analyze new JWST NIRCam and NIRSpec data on the redshift 9.11 galaxyMACS1149-JD1. Our NIRCam imaging data reveal that JD1 comprises three spatiallydistinct components. Our spectroscopic data indicate that JD1 appears dust-freebut is already enriched, $12 + \log {\rm (O/H) } = 7.90^{+0.04}_{-0.05}$. Wealso find that the Carbon and Neon abundances in JD1 are below the solarabundance ratio. Particularly the Carbon under-abundance is suggestive ofrecent star formation where Type~II supernovae have already enriched the ISM inOxygen but intermediate mass stars have not yet enriched the ISM in Carbon. Arecent burst of star formation is also revealed by the star formation historyderived from NIRCam photometry. Our data do not reveal the presence of asignificant amount of old populations, resulting in a factor of $\sim7\times$smaller stellar mass than previous estimates. Thus, our data support the viewthat JD1 is a young galaxy.

The puzzling properties of the MACS1149-JD1 galaxy at z=9.11