The value of density measurements in stellar coronae
Abstract
The grating instruments on board Chandra and XMM-Newton now allow measurements of electron densities. These rely on the ratios of fluxes in emission lines, where one line depends on both collisional and radiative decay rates. The electron density is required to constrain the physical extent of the emitting region, and large samples of measurements are of interest in the context of trends in coronal activity. Here we discuss the important He {\sc i}-like ions and the differences in densities that result when different current data bases are used.
- Publication:
-
X-ray Diagnostics of Astrophysical Plasmas: Theory, Experiment, and Observation
- Pub Date:
- June 2005
- DOI:
- 10.1063/1.1960928
- arXiv:
- arXiv:astro-ph/0504146
- Bibcode:
- 2005AIPC..774..187N
- Keywords:
-
- stellar atmospheres;
- plasma density;
- astrophysical plasma;
- X-ray sources (astronomical);
- 97.10.Ex;
- 95.85.Nv;
- 95.30.Qd;
- Stellar atmospheres;
- radiative transfer;
- opacity and line formation;
- X-ray;
- Magnetohydrodynamics and plasmas;
- Astrophysics
- E-Print:
- 3 pages, 3 figures, proceedings ITAMP Workshop: X-ray Diagnostics for Astrophysical Plasmas: Theory, Experiment and Observation. 2004 November 15-17 Cambridge, USA