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Author Pottasch, S. R.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PHYSICS ♦ ASTROPHYSICS ♦ ATMOSPHERE ♦ COLLISIONS ♦ DENSITY ♦ ELECTRONS ♦ EMISSION ♦ ENERGY LEVELS ♦ HELIUM ♦ MEASURED VALUES ♦ NEBULAE ♦ SPECTRA ♦ SPECTROSCOPY
Abstract Relative intensities of emission lines in the trtplet system of neutral He are determined as a function of the optical depth of an atmosphere in lambda 3889. The atmosphere considered is one of low density, comparable to nebulae, to minimize the importance of effects due to electron collisions. The range of optical depth considered is limited so that only lines originating from the metastable 23S level show effects of optical depth. Thus THETA (l0830) < 10, since above this value the population of the 23P level becomes large enough such that the optical depth in lines arising from that level cannot be ignored. A comparison with the He observations of 5 well-known nebulae shows the effects of optical depth in 3 and probably 4 of these nebula. (auth)
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 1962-03-01
Publisher Department Princeton Univ. Observatory and Inst. for Advanced Study, Princeton, N.J.
Journal Astrophysical Journal
Volume Number 135
Organization Princeton Univ. Observatory and Inst. for Advanced Study, Princeton, N.J.


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