An Accurate EUV/X-ray Line Ratio Diagnostic
Abstract
We propose to calculate accurate collisional excitation rate data for Fe XVIII. The EUV/X-ray line ratio is of particular interest to stellar coronae and other collisionally ionized sources observed with the Chandra LETG/HRC-S. Comparison of observations of Capella and other stellar coronal sources with predictions from existing atomic theory shows discrepancies of 30% and larger in the EUV/X-ray line ratios for Fe XVIII. With atomic data accurate to 10%, now achievable with atomic theory benchmarked by experiment, this line ratio from a single ionization state is useful for determining electron temperature and/or interstellar absorption.
- Publication:
-
Chandra Proposal
- Pub Date:
- September 2011
- Bibcode:
- 2011cxo..prop.4225B