X‐Ray Spectroscopy of η 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 (RGS). The European Photon Imaging Camera (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 similar to0.15-0.6 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.