Astronomy and Astrophysics – Astronomy
Scientific paper
May 2007
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007iaus..243..103a&link_type=abstract
Star-Disk Interaction in Young Stars, Proceedings of the International Astronomical Union, IAU Symposium, Volume 243, p. 103-114
Astronomy and Astrophysics
Astronomy
1
Stars: Atmospheres, Coronae, Winds, Outflows, Line: Formation, Magnetic Fields, Ultraviolet: Stars, X-Rays: Stars
Scientific paper
I review our current understanding of accretion shocks in classical T Tauri stars (CTTs), from a UV and X-ray perspective. The region of the accretion shock is a good candidate as a source of UV transition region lines from Li/Na-like ions, which are stronger in CTTs than in naked atmospheres. Disk gas captured by the stellar magnetic field produces a strong radiative shock upon falling on the stellar surface. Radiation from the shock creates a radiative precursor and heats the stellar surface resulting in a hot spot. Stellar and shock models indicate that unless the post-shock column is very large, it will be buried on the stellar photosphere. Models of the continuum emission produced by this configuration can roughly reproduce the observed excess spectra down to 1650 Å. Transition region lines in CTTs are broad, very variable, and present blueshifted, centered, and redshifted centroids. Detailed models of the line emission have so far failed to reproduce the fluxes, line shapes, and line ratios. High resolution X-ray line observations indicate the presence of larger amounts of cool plasma in CTTs with respect to WTTs. Observations of density sensitive line ratios of He-like ions suggest high plasma densities, as expected from lines originating in the accretion shock. For most stars, the interpretation of these ratios in terms of density remains equivocal due to the presence of the strong UV continuum.
No associations
LandOfFree
Observations of accretion shocks 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 Observations of accretion shocks, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Observations of accretion shocks will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-770288