Temperature fluctuations and starburst evolution

The understanding of temperature fluctuations in ionized nebulae is a key problem in the computation of chemical abundances, which bears on a variety of fundamental issues in astronomy. Although the problem was stated three decades ago, its impact on the values of the abundances remains challenged, mainly because it is an ill-defined one from the observational point of view. In this work we investigate the change of the ionization structure during the first 7 Myr of the evolution of a starburst. We show that large temperature fluctuations arise naturally when the spectral energy distribution of the ionizing cluster hardens during the Wolf-Rayet phase.