Abstract
One measure of progress in research on interstellar matter is our expanded awareness of the broad variations in the physical state of material dispersed throughout our galaxy. As they become recognized, the various regimes of density, temperature and ionization are often characterized as discrete “phases,” although in some circumstances the boundaries between such phases may not be as well defined as we once thought. At one end of the spectrum of conditions are the compact gas clouds, rich in dust grains and complex molecules, having temperatures below a few tens of degrees K and densities in excess of 10−19 g cm−3. If we exclude suprathermal particles (cosmic rays), we may identify the other extreme as collisionally ionized gas with a temperature on the order of 105 to 107 K and a mean density of around 10−27 g cm−3.
Keywords
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsEditor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1977 D. Reidel Publishing Company, Dordrecht, Holland
About this chapter
Cite this chapter
Jenkins, E.B. (1977). Introduction. In: Van Woerden, H. (eds) Topics in Interstellar Matter. Astrophysics and Space Science Library, vol 70. Springer, Dordrecht. https://doi.org/10.1007/978-94-010-1254-6_1
Download citation
DOI: https://doi.org/10.1007/978-94-010-1254-6_1
Publisher Name: Springer, Dordrecht
Print ISBN: 978-94-010-1256-0
Online ISBN: 978-94-010-1254-6
eBook Packages: Springer Book Archive