منابع مشابه
Astronomy and Astrophysics Spectroscopic Investigation of Old Planetaries v. Distance Scales
We use the results of our recent NLTE model atmosphere analysis of central stars of old planetary nebulae (PN) to calculate distances. We perform a comparison with three other methods (trigonometric parallaxes, interstellar NaD lines, and Shklovsky distances) and discuss the problem of the PNe distance scale. The result of the comparison of our spectroscopic distances with the trigonometric dis...
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We present a detailed spectroscopic analysis of the H and He i spectrum of the Luminous Blue Variable (LBV) P Cygni. The observational constraints for our investigation are given by the mean optical and near-IR spectra obtained by Stahl et al. (1993) and published UV, optical, IR and radio continuum measurements of the star. Within the parameter domain of interest we have investigated how line ...
متن کاملPopular astronomy.
The Springer-Praxis Popular Astronomy programme covers the latest observations, techniques and discoveries in astronomy, astrophysics and cosmology, selecting key topics designed to fire the imagination of keen astronomers everywhere. Many of the topics selected for titles in this programme are refreshingly new, and away from the accepted mainstream of titles published in this area. Topics inc...
متن کاملPopular astronomy.
The Springer-Praxis Popular Astronomy programme covers the latest observations, techniques and discoveries in astronomy, astrophysics and cosmology, selecting key topics designed to fire the imagination of keen astronomers everywhere. Many of the topics selected for titles in this programme are refreshingly new, and away from the accepted mainstream of titles published in this area. Topics inc...
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Pr in te d in th e U SA $4 .9 5 $7 .9 5 C A N LIGHT Wave description: The periodic oscillation of electric and magnetic fields in space. Characterized by the following: 1. Frequency of the oscillation, ν , measured in cycles per second (hertz). 2. Wavelength of the oscillation, λ, measured in meters. This is the distance from one peak to the next. • Wave equation: All light travels at a finite ...
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ژورنال
عنوان ژورنال: Nature
سال: 1919
ISSN: 0028-0836,1476-4687
DOI: 10.1038/104234a0