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We report the serendipitous discovery of an extended stellar halo surroundingthe low-mass galaxy Ark 227 ($M_\ast=5\times10^9 M_\odot$; d=35 Mpc) in deepJWST NIRCam imaging from the Blue Jay Survey. The F200W-F444W color providesrobust star-galaxy separation, enabling the identification of stars at very lowdensity. By combining resolved stars at large galactocentric distances withdiffuse emission from NIRCam and Dragonfly imaging at smaller distances, wetrace the surface brightness and color profiles of this galaxy over the entireextent of its predicted dark matter halo, from 0.1-100 kpc. Controlled N-bodysimulations have predicted that minor mergers create "accretion shelves" in thesurface brightness profile at large radius. We observe such a feature in Ark227 at 10-20 kpc, which, according to models, could be caused by a merger withtotal mass ratio 1:10. The metallicity declines over this radial range, furthersupporting the minor merger scenario. There is tentative evidence of a secondshelf at $\mu_V\approx 35$ mag arcsec$^{-2}$ extending from 50-100 kpc, alongwith a corresponding drop in metallicity. The stellar mass in this outermostenvelope is $\approx10^7M_\odot$. These results suggest that Ark 227experienced multiple mergers with a spectrum of lower-mass galaxies -- ascenario that is broadly consistent with the hierarchical growth of structurein a cold dark matter-dominated universe. Finally, we identify an ultra-faintdwarf associated with Ark 227 with $M_\ast\approx10^5 M_\odot$ and$\mu_{V,e}=28.1$ mag arcsec$^{-2}$, demonstrating that JWST is capable ofdetecting very low-mass dwarfs to distances of at least ~30 Mpc.

Detection of Accretion Shelves Out to the Virial Radius of a Low-Mass Galaxy with JWST