Program: GN-2007B-Q-116

Title:Providing a zero point for absolute nebula abundances:Massive stars in M31.
PI:Carrie Trundle
Co-I(s): Stephen Smartt, Fabio Bresolin, Almudena Azurita, Martin Cordiner, Nick Cox, Daniel Lennon, Philip Dufton, Christopher Evans, David Young, John Eldridge

Abstract

Stars towards M31's centre are generally assumed to be metal rich, an assumption based on abundances derived from HII regions using indirect methods. Recent work on nebulae in another spiral galaxy, M51, showed that applying direct, rather than indirect, methods can lead to a substantial decrease in nebular oxygen abundances. Such a reduction in abundance will have a significant impact on metallicity measurements in Starburst galaxies, the environments of supernovae and gamma-ray bursts, and the chemical evolution of galaxies. However an independent metallicity diagnostic is required to validate these results. We propose to investigate abundances of M31's B-type star population, providing a fundamental test of `direct' and `indirect' nebular abundances. In conjunction with recently obtained nebula spectra, this will provide two independent studies of M31's metallicity and provide a secure zero point for indirect nebular abundance calibrations.

Publications using this program's data