Published Online: 15 SEP 2006
Copyright © 2000 John Wiley & Sons, Ltd. All rights reserved.
Encyclopedia of Analytical Chemistry
How to Cite
Porter, J. M. and Steele, I. A. 2006. Stellar Spectroscopy. Encyclopedia of Analytical Chemistry. .
- Published Online: 15 SEP 2006
Spectroscopy started with the examination of the Sun's light, making stellar spectroscopy the oldest branch of the subject. We describe modern stellar spectroscopy, and highlight some of the major successes in understanding the light output from stars and what we can deduce about the underlying objects. We present a description of stellar atmospheres considering the mechanical structure and the transport of energy. This leads on to a discussion of how the continuum and spectral lines of stellar spectra are formed and an explanation of the main features observed. The spectral lines observed in stellar spectra are then discussed and the information which can be obtained from examining their line shapes is examined. These include atmospheric pressure and temperature and both coherent and turbulent velocity fields (from stellar rotation and atmospheric convection currents). Magnetic fields, if large enough, may also be detected from careful examination of spectral lines.
Following a discussion of some practical aspects of observing stars, the main observational stellar classification scheme is presented, along with its interpretation regarding the underlying mass, radius, temperatures and evolutionary phase of the star. The effect of the chemical composition on line strengths is discussed, along with observational techniques of measuring it. The information which is obtained from different wavelength regimes – from radio waves to γ-rays – is presented, along with possible difficulties associated with observing in each regime.
Finally, we discuss what we have learnt from examination of stellar spectra and the current state of theory which is applied to them.