Coronal density diagnostics with Si X: CHANDRA/LETGS observations of Procyon, $α$ Cen A$&$B, Capella and $ε$ Eri

Details Coronal density diagnostics with Si X: CHANDRA/LETGS observations of Procyon, $α$ Cen A$&$B, Capella and $ε$ Eri Coronal density diagnostics with Si X: CHANDRA/LETGS observations of Procyon, $α$ Cen A$&$B, Capella and $ε$ Eri

2006-04-10

arxiv.org/abs/astro-ph/0604188v1

Astron.J.132:371-377,2006

Astronomy and Astrophysics

Astrophysics

24 pages. The Astronomical Journal Accepted

Scientific paper

10.1086/505041

Electron density diagnostics based on a line intensity ratio of Si X are applied to the X-ray spectra of Procyon, $\alpha$ Cen A$&$B, Capella and $\epsilon$ Eri measured with the Low Energy Transmission Grating Spectrometer (LETGS) combined with High-resolution Camera (HRC) on board the {\it Chandra X-ray Observatory}. The ratio $R_1$ of the intensities of the Si X lines at 50.524 \AA and 50.691 \AA is adopted. A certain of the temperature effect in $R_1$ appears near the low-density limit region, which is due to the contamination of Si X line at 50.703 \AA . Using the emission measure distribution (EMD) model derived by Audard et al. (2001) for Capella and emissivities calculated with APEC model by Smith et al. (2001), we successfully estimate contributions of Fe XVI lines at 50.367 \AA and 50.576 \AA (73% and 62%, respectively). A comparison between observed ratios and theoretical predictions constrains the electron densities (in logarithmic) for Procyon to be 8.61$^{+0.24}_{-0.20}$ cm$^{-3}$, while for $\alpha$ Cen A$&$B, Capella and $\epsilon$ Eri to be 8.81$^{+0.27}_{-0.23}$ cm$^{-3}$, 8.60$^{+0.39}_{0.32}$ cm$^{-3}$, 9.30$_{-0.48}$ cm$^{-3}$ and 9.11$^{+1.40}_{-0.38}$ cm$^{-3}$, respectively. The comparison of our results with those constrained by the triplet of He-like carbon shows a good agreement. For normal stars, our results display a narrow uncertainty, while for active stars, a relatively larger uncertainty, due to the contamination from Fe XVI lines, is found. Another possible reason may be that the determination of the continuum level, since the emission lines of Si X become weak for the active stars. For $\epsilon$ Eri, an electron density in the C V forming region was estimated firstly through Si X emissions.

Affiliated with

Also associated with

No associations

Rating

Coronal density diagnostics with Si X: CHANDRA/LETGS observations of Procyon, $α$ Cen A$&$B, Capella and $ε$ Eri does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Coronal density diagnostics with Si X: CHANDRA/LETGS observations of Procyon, $α$ Cen A$&$B, Capella and $ε$ Eri, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coronal density diagnostics with Si X: CHANDRA/LETGS observations of Procyon, $α$ Cen A$&$B, Capella and $ε$ Eri will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-701320