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We present stellar parameters and chemical abundances of 30 elements for fivestars located at large radii (3.5-10.7 times the half-light radius) in theSextans dwarf spheroidal galaxy. We selected these stars using proper motions,radial velocities, and metallicities, and we confirm them as metal-poor membersof Sextans with -3.34 <= [Fe/H] <= -2.64 using high-resolution optical spectracollected with the Magellan Inamori Kyocera Echelle spectrograph. Four of thefive stars exhibit normal abundances of C (-0.34 <= [C/Fe] <= +0.36), mildenhancement of the alpha elements Mg, Si, Ca, and Ti ([alpha/Fe] = +0.12 +/-0.03), and unremarkable abundances of Na, Al, K, Sc, V, Cr, Mn, Co, Ni, and Zn.We identify three chemical signatures previously unknown among stars inSextans. One star exhibits large overabundances ([X/Fe] > +1.2) of C, N, O, Na,Mg, Si, and K, and large deficiencies of heavy elements ([Sr/Fe] = -2.37 +/-0.25, [Ba/Fe] = -1.45 +/- 0.20, [Eu/Fe] < +0.05), establishing it as a memberof the class of carbon-enhanced metal-poor stars with no enhancement ofneutron-capture elements. Three stars exhibit moderate enhancements of Eu(+0.17 <= [Eu/Fe] <= +0.70), and the abundance ratios among 12 neutron-captureelements are indicative of r-process nucleosynthesis. Another star is highlyenhanced in Sr relative to heavier elements ([Sr/Ba] = +1.21 +/- 0.25). Thesechemical signatures can all be attributed to massive, low-metallicity stars ortheir end states. Our results, the first for stars at large radius in Sextans,demonstrate that these stars were formed in chemically inhomogeneous regions,such as those found in ultra-faint dwarf galaxies.

Abundance Analysis of Stars at Large Radius in the Sextans Dwarf Spheroidal Galaxy