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  • Electronic Resource  (6)
  • 1995-1999  (5)
  • 1940-1944  (1)
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  • Electronic Resource  (6)
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  • 1
    Electronic Resource
    Electronic Resource
    Comments on some possible models of TMC-1 (1996)
    Springer
    Astrophysics and space science 238 (1996), S. 303-308 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Chemical differences between cores in the dark ridge TMC-1 have been attributed to the cores being in different stages of chemical evolution with those having high NH3 to cyanopolyyne abundance ratios being the most evolved. We suggest several alternative models including one in which the highest NH3 to cyanopolyyne abundance ratio obtains in the youngest TMC-1 core; in this and in one of the other models the evolution of the chemistry as depletion increases is supposed to lead to a lower NH3 to cyanopolyyne ratio. The possibility that the cyanopolyynes exist primarily in an interface between dark core material and the wind of a low mass star is considered; this wind interface model may account for the sharp cyanopolyyne emission gradient on the side of the ridge away from the star. Implosion of the cores by the ram pressure of the wind may have caused them to collapse more rapidly than gravity could and more rapidly than chemistry evolves so that the chemistry reflects a core's state at a lower density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00641694
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Molecules in Boundary Layers in Planetary Nebulae (1997)
    Springer
    Astrophysics and space science 251 (1997), S. 275-279 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1000727310171
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    A Census of Atmospheric Pollen (1943)
    [s.l.] : Nature Publishing Group
    Nature 151 (1943), S. 82-83 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] THE pollen content of the atmosphere is of interest in relation to general plant biology, the pollen analysis of peats and the study of allergic diseases such as hay fever and asthma. This subject was first investigated by Blackley1 in Great Britain and has since been pursued on ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/151082b0
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Book reviews (1995)
    Springer
    Astrophysics and space science 229 (1995), S. 341-343 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00626875
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  • 5
    Electronic Resource
    Electronic Resource
    Revised chemical models of ζ Oph based on HST data (1996)
    Springer
    Astrophysics and space science 236 (1996), S. 257-265 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Hubble Space Telescope observations by Savage, Cardelli and Sofia (1992) and Cardelliet al. (1993) have led to improved gas phase abundances for many elements in the diffuse cloud towards the star ζ Oph. Most remarkably, it was found that oxygen is much more strongly depleted than previousCopernicus observations indicated. As a consequence, chemical models of the ζ Oph cloud are severely affected by the drop in the observed oxygen abundance by almost a factor of two; some previous model calculations for the ζ Oph cloud failed to reproduce-even approximately-the observed high CO column density. The model calculations for the ζ Oph cloud developed by Wagenblast (1992) in which the abundance of all observed neutral molecules could be reproduced have been revised and it is found that oxygen and nitrogen hydrides are required to be formed efficiently on the surface of grains; further, there are indications for a high cosmic ray ionization rate of the order 10−16 s−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00645147
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  • 6
    Electronic Resource
    Electronic Resource
    The identification of diffuse bands (1996)
    Springer
    Astrophysics and space science 237 (1996), S. 243-266 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Our present knowledge of the diffuse interstellar bands (two of which were first noted by Wilson in 1958) is briefly summarized. Other broad and very broad interstellar features (the 220nm extinction bump, the very broad structure in the extinction curve, the extended red emission in reflection and other nebulae, and the unidentified-sometimes called the “overidentified”-infrared bands) are also briefly described. The origins of all these features remain unknown, in spite of intensive study. Possible relations between these various features and families is briefly discussed. Recent observations are shown to support the hypothesis that the carriers of the diffuse bands are free-flying molecules, whereas the alternative hypothesis of dust grains now seems to be untenable. Candidate types of molecular carriers are mentioned, and the possible source of such molecules in the diffuse interstellar medium is briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02424434
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