Ring Nebulae: Tracers of the CNO Nucleosynthesis

TL;DR

This study presents spectroscopic observations of Galactic ring nebulae to analyze their chemical compositions, providing insights into CNO nucleosynthesis and stellar evolution models.

Contribution

First detailed spectroscopic analysis of multiple Galactic ring nebulae focusing on CNO element lines to test stellar nucleosynthesis predictions.

Findings

Detection of recombination lines of C II, O II, and N II in NGC 6888

Chemical content consistent with massive star evolution models

High signal-to-noise ratio observations enable precise abundance measurements

Abstract

Preliminary results are presented from spectroscopic data in the optical range of the Galactic ring nebulae NGC 6888, G2:4+1:4, RCW 58 and Sh2-308. Deep observations with long exposure times were carried out at the 6.5m Clay Telescope and at the 10.4m Gran Telescopio Canarias. In NGC 6888, recombination lines of C II, O II and N II are detected with signal-to-noise ratios higher than 8. The chemical content of NGC 6888 is discussed within the chemical enrichment predicted by evolution models of massive stars. For all nebulae, a forthcoming work will content in-depth details about observations, analysis and final results (Esteban et al. 2015, in prep.).