Optical Spectroscopy of V4334 Sgr: 1996–2000

Due to a combination of rapid expansion and changes in chemical composition, the optical spectrum of V4334 Sgr changed rapidly between discovery in 1996 Februaryand extinction during 1999. As one of the most rapidly evolving stars ever observed, optical spectroscopy must answer a range of important questions.The development of the optical spectrum and its implications are discussedthrough a review of published literature. A previously unpublished sequence of spectra from near discovery through 1996 demonstrates the thermal evolution of V4334 Sgr, while detailed analysis of an unpublished echelle spectrumobtained in 1996 May raises questions about the model atmospheres used to date.As a result, requirements for future models of the atmosphere of V4334 Sgr are analysed. The future evolution of V4334 Sgr and the dispersion of its dustycocoon are briefly discussed.