AST 341 Lecture Notes - Lecture 6: Elastic Collision, Compton Wavelength, Main Sequence
17 Dec 2016
School
Department
Course
Professor
Document Summary
By now we have developed enough tools that we are able to make a more detailed analysis of spectral lines. This is a very important topic in astrophysics, since the shape of an individual spectral line contains a wealth of information about the environment in which it was formed. We have discussed how an individual atom making a transition between energy levels emits one photon with a well-de ned energy/frequency. However, pro les of real spectral lines are not in nitely narrow. If fc is the continuum level, the quantity (fc f )/fc is referred to as the depth of the line. The strength of a spectral line is measured in terms of its equivalent width w. this is de ned as the width of a box reaching up to the continuum that has the same area as the spectral line.
