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This paper presents a millimeter wavelength aperture-synthesis study of thespatial variations of the chemistry in the envelope around the deeply embeddedlow-mass protostar L483-mm on 1000 AU (5") scales. Lines of 8 molecular speciesincluding CN, C18O, CS, C34S, HCN, H13CN, HCO+ and N2H+ have been observedusing the Owens Valley Radio Observatory Millimeter Array. Continuum emissionat 2.7-3.4 millimeter is well-fit by a pure envelope model down to thesensitivity of the interferometer without introducing a disk/compact source, incontrast to what is seen for other protostars. A velocity gradient in thedensest material is traced by HCN, CS and N2H+, and is perpendicular to thelarge-scale CO outflow, with a pattern consistent with rotation around a 1solar mass central object. Velocity gradients in the propagation direction ofthe outflow suggest a clear interaction between the outflowing material and"quiescent" core. The C18O observations are fit with a "drop" abundance profilewhere CO is frozen-out in a region of the envelope with temperatures lower than40 K and densities higher than 1.5e5 cm^{-3}, which is also required toreproduce single-dish observations. The N2H+ emission strongly resembles thatof NH3 and is found to be absent toward the central continuum source. This is adirect consequence of the high CO abundances in the inner region as illustratedby a chemical model for the L483 envelope. The observed CN emission forms aspatial borderline between the outflowing and quiescent material probed by,respectively, HCO+ and N2H+, and also shows intermediate velocities compared tothese two species. A scenario is suggested in which CN is enhanced in the wallsof an outflow cavity due to the impact of UV irradiation either from thecentral protostellar system or related to shocks caused by the outflow.Comment: Accepted for publication in A&A. 14 pages, 14 figure

Imaging chemical differentiation around the low-mass protostar L483-mm