399 research outputs found
A catalogue of Paschen-line profiles in standard stars
We have assembled an atlas of line profiles of the Paschen Delta line at
10,049 angstroms for the use of stellar modelling. For a few stars we have
substituted the Paschen Gamma line at 10,938 angstroms because the Paschen
Delta line blends with other features. Most of the targets are standard stars
of spectral types from B to M. A few metal-poor stars have been included. For
many of the stars we have also observed the Hydrogen Alpha line so as to
compare the profiles of lines originating from the meta-stable n=2 level with
lines originating from the n=3 level. The greatest difference in line profile
is found for high luminosity and cool stars where the departures from LTE in
the population of the n=2 level is expected to be the greatest.
For a few stars, sample line profiles have been calculated in the LTE
approximation to demonstrate the usefulness of the tabulated and displayed
catalogue
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