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Record Details

Record 29 of 1230
Neutron stars and white dwarfs in galactic halos?
External Online Source: doi:10.1086/168591
Author and Affiliation:
Ryu, Dongsu(NASAFermilab Astrophysics Center, Batavia, IL, United States)
Olive, Keith A.(Minnesota, University, Minneapolis, United States)
Silk, Joseph(California, University, Berkeley, United States)
Abstract: The possibility that galactic halos are composed of stellar remnants such as neutron stars and white dwarfs is discussed. On the basis of a simple model for the evolution of galactic halos, researchers follow the history of halo matter, luminosity, and metal and helium abundances. They assume conventional yields for helium and the heavier elements. By comparing with the observational constraints, which may be considered as fairly conservative, it is found that, for an exponentially decreasing star formation rate (SFR) with e-folding time tau, only values between 6 x 10(8) less than similar to tau less than similar to 2 x 10(9) years are allowed together with a very limited range of masses for the initial mass function (IMF). Star formation is allowed for 2 solar mass less than similar to m less than similar to 8 solar mass if tau = 2 x 10(9) years, and for 4 solar mass less than similar to m less than similar to 6 solar mass if tau = 10(9) years. For tau = 6 x 10(8) years, the lower and upper mass limits merge to similar to 5 solar mass. Researchers conclude that, even though the possibility of neutron stars as halo matter may be ruled out, that of white dwarfs may still be a viable hypothesis, though with very stringent constraints on allowed parameters, that merits further consideration.
Publication Date: Apr 10, 1990
Document ID:
19900043854
(Acquired Nov 28, 1995)
Accession Number: 90A30909
Subject Category: ASTROPHYSICS
Document Type: Journal Article
Publication Information: Astrophysical Journal, Part 1 (ISSN 0004-637X); 353; 81-89
Publisher Information: United States
Contract/Grant/Task Num: DE-AC02-83ER-40105; NAGW-1340
Financial Sponsor: NASA; United States
Organization Source: NASA Lewis Research Center; Cleveland, OH, United States
Fermi National Accelerator Lab.; Batavia, IL, United States
Minnesota Univ.; Minneapolis, MN, United States
California Univ.; Berkeley, CA, United States
Description: 9p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: GALACTIC HALOS; GALAXIES; HALOS; NEUTRON STARS; STELLAR EVOLUTION; WHITE DWARF STARS; HELIUM; LUMINOSITY; MATHEMATICAL MODELS
Imprint And Other Notes: Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 353, April 10, 1990, p. 81-89. Research supported by NSF. Previously announced in STAR as N89-26783.
Miscellaneous Notes: Research supported by NSF. Previously announced in STAR as N89-26783
Availability Source: Other Sources
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