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Paper: Surprises from the Type Ia SN 2003du
Volume: 342, 1604-2004: Supernovae as Cosmological Lighthouses
Page: 250
Authors: Gerardy, C.L.
Abstract: We summarize our analysis of optical and near-infrared observations of the Type Ia supernova 2003du. This event seems to have been relatively normal, but when closely scrutinized, the early- and late-time spectral evolutions provide surprising insights. The early-time optical evolution exhibits a high-velocity component in the Ca II “Infrared Triplet” feature which we show can be explained as absorption from a dense shell of swept up circumstellar material. Our analysis suggests that observations of the IR triplet feature can be used to probe the circumstellar environment of Type Ia SNe, providing constraints on the mass and location of loosely bound material in the progenitor system. Late-time NIR observations of SN 2003du show a flat-topped emission profile in the 1.64 micron [Fe II] feature, which may be the signature of high-density burning during the thermonuclear deflagration. This seems to be at odds with the predictions of 3D deflagration models (at least in static WDs) and thus this observation may be an important clue as to the nature of the earliest phases of nuclear burning in SNe Ia. The results summarized here are given a full account in two separately published papers (Gerardy et al. 2004; Hoeflich et al. 2004).
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