Planetary nebulae are a keystone for the understanding of the evolution of stars, for deep insights into the physical processes prevailing in highly excited dilute nebulae, and for the chemical evolution in galaxies. These objects, displaying an intriguing morphology, have a `short' lifetime of a few tens of thousands of years, and have become one of the best studied classes of celestial sources. However, despite large and successful efforts from both the observational and theoretical side, planetary nebulae still keep some of their secrets (like the widely unknown distances) and will undoubtedly also be objects of thorough investigations in the years to come.(4) 1 T (K) 400 500 750 400 2 Go 1. (4) 4. ... Since the incident FUV field (alt;13.6 eV) will decrease due to geometrical dilution, the temperature in the neutral gas will slowly drop and the ... Adopting a hot black body, N*=6.3x1052/Teff photons s a#39; for L=6000Lo and N=2x1011 [105K/Teft|OS [5x1016/r(cm)] photons s.l. Thus, the anbsp;...
|Author||:||R. Weinberger, A. Acker|
|Publisher||:||Springer Science & Business Media - 2012-12-06|