X-ray spectroscopy of Eta Carinae with XMM-Newton

Abstract

We present XMM-Newton observations of the luminous star Eta Carinae, including a high resolution soft X-ray spectrum of the surrounding nebula obtained with the Reflection Grating Spectrometer. The EPIC image of the field around Eta Car shows many early-type stars and diffuse emission from hot, shocked gas. The EPIC spectrum of the star is similar to that observed in previous X-ray observations, and requires two temperature components. The RGS spectrum of the surrounding nebula shows K-shell emission lines from hydrogen- and helium-like nitrogen and neon and L-shell lines from iron, but little or no emission from oxygen. The observed emission lines are not consistent with a single temperature, but the range of temperatures observed is not large, spanning ~0.15-0.6 keV. We obtain upper limits for oxygen line emission and derive a lower limit of N/O > 9. This is consistent with previous abundance determinations for the ejecta of Eta Car, and with theoretical models for the evolution of massive, rotating stars.