Book contents
- Frontmatter
- Contents
- Preface to the first edition
- Preface to the second edition
- Preface to the third edition
- 1 Background
- 2 Fourier transforms
- 3 Spectroscopic tools
- 4 Light detectors
- 5 Radiation terms and definitions
- 6 The black body and its radiation
- 7 Radiative and convective energy transport
- 8 The continuous absorption coefficient
- 9 The model photosphere
- 10 The measurement of stellar continua
- 11 The line absorption coefficient
- 12 The measurement of spectral lines
- 13 The behavior of spectral lines
- 14 The measurement of stellar radii and temperatures
- 15 The measurement of photospheric pressure
- 16 Chemical analysis
- 17 Velocity fields in stellar photospheres
- 18 Stellar rotation
- Appendix A A table of useful constants
- Appendix B Physical parameters of stars
- Appendix C A fast Fourier transform Fortran program
- Appendix D Atomic data
- Appendix E The strongest lines in the solar spectrum
- Appendix F Computation of random errors
- Index
- References
1 - Background
Published online by Cambridge University Press: 05 March 2015
- Frontmatter
- Contents
- Preface to the first edition
- Preface to the second edition
- Preface to the third edition
- 1 Background
- 2 Fourier transforms
- 3 Spectroscopic tools
- 4 Light detectors
- 5 Radiation terms and definitions
- 6 The black body and its radiation
- 7 Radiative and convective energy transport
- 8 The continuous absorption coefficient
- 9 The model photosphere
- 10 The measurement of stellar continua
- 11 The line absorption coefficient
- 12 The measurement of spectral lines
- 13 The behavior of spectral lines
- 14 The measurement of stellar radii and temperatures
- 15 The measurement of photospheric pressure
- 16 Chemical analysis
- 17 Velocity fields in stellar photospheres
- 18 Stellar rotation
- Appendix A A table of useful constants
- Appendix B Physical parameters of stars
- Appendix C A fast Fourier transform Fortran program
- Appendix D Atomic data
- Appendix E The strongest lines in the solar spectrum
- Appendix F Computation of random errors
- Index
- References
Summary
We study stellar spectra, including both lines and continua, because we are interested in the nature of the star's atmosphere. The behavior of the atmosphere is controlled by the density of the gases in it and the energy escaping through it. These in turn depend on the mass and age of the star and to a lesser extent on chemical composition and angular momentum. Stellar atmospheres are the connecting links between the observations and the rest of stellar astrophysics. In this way two philosophies arise. One is the study of the atmosphere for its own sake and the other is the use of the atmosphere as a tool to connect our observations to other parameters of interest. This book should be useful for students of both philosophies.
The topics brought together to form this chapter are background material which the reader will need. The more advanced reader can profitably skim through to Chapter 2.
What is a stellar atmosphere?
A stellar atmosphere is a transition region from the stellar interior to the interstellar medium. One way to quantify this description is to look at the change in average kinetic temperature with height as observed in the Sun. Figure 1.1 shows the solar temperature profile with the four basic sections labeled, sub-photosphere, photosphere, chromosphere, and corona. For an observer of stellar atmospheres, one concept is very important: the major portion of the visible stellar spectrum originates in the region marked “photosphere.” A study of the visible-light spectrum is essentially a study of the photosphere.
- Type
- Chapter
- Information
- The Observation and Analysis of Stellar Photospheres , pp. 1 - 25Publisher: Cambridge University PressPrint publication year: 2005
References
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