Seismic tests of the Sun's interior structure, composition, and age, and implications for solar neutrinos

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dc.creator Guenther, David B.
dc.creator Demarque, P.
dc.date.accessioned 2015-02-02T19:28:20Z
dc.date.available 2015-02-02T19:28:20Z
dc.date.issued 1997-08
dc.identifier.issn 0004-637X
dc.identifier.uri http://library2.smu.ca/xmlui/handle/01/25938
dc.description Publisher's version/PDF en_CA
dc.description.abstract The structure of the deep interior of a variety of standard and nonstandard solar models constrained by the low-l p-mode oscillation data from GONG are presented. For standard models, we show that the effects of both helium and heavy-element diffusion must be included in order to find simultaneous agreement with both the p-mode spectrum and the observed value of (Z/X)[subscript circled dot]. Related to this conclusion, we find that the average interior heavy-element abundance is greater than the observed surface abundance in models whose small spacings, which are derived from the p-mode oscillation spectra, best match the observations. The high-quality data from the Global Oscillation Network Group (GONG) now permit a precise determination of the seismic age of the Sun. The best agreement with the calculated oscillation spectra is achieved for 4.5 [plus or minus] 0.1 Gyr, an age closely consistent with the age of the Sun inferred from meteorites, i.e., 4.53 [plus or minus] 0.04 Gyr. This result lends strong support to the standard assumption of the theory of stellar evolution. With regard to the nonstandard solar models, we set limits on the extent to which the nonstandard assumptions can be applied to the model while still being consistent with the observed p-modes. The nonstandard assumptions investigated here are: forced mixing in the core, forced mixing in a shell surrounding the core, and near-zero heavy-element abundance in the core. These assumptions were selected because at one time or another they have all been proposed to reduce the neutrino flux of the solar model, thereby bringing the flux of the model more in line with the observed flux. All nonstandard models include helium and heavy element diffusion. We confirm, now using the latest solar model physics, that these nonstandard assumptions, when capable of reducing significantly the solar neutrino flux, perturb the interior structure too much to be consistent with p-mode observations. In addition, we set strict limits on the extent to which these nonstandard assumptions are tolerated by the current p-mode observations. For example, we show that the p-mode small spacings are incompatible with a low-Z core larger than 0.06 M[subscript circled dot] in the Sun. And we show that if the Sun's core is chemically mixed, the extent of the mixed core cannot exceed 0.02 M[subscript circled dot]. The seismic data are also incompatible with extensive rapid mixing of [superscript 4]He in the solar envelope. This, we believe, also argues against the possibility of slow mixing of [superscript 3]He occurring in a shell, as was recently proposed by Cumming and Haxton to lower the [superscript 7]Be/[superscript 8]B neutrino flux ratio. But we note that the occurrence of some mixing of [superscript 3]He and other trace elements and isotopes in the region of the solar interior where the initial [superscript 4]He abundance is nearly uniform (which could not at this point be detected by seismology) might modify the calculated neutrino fluxes. en_CA
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dc.description.provenance Made available in DSpace on 2015-02-02T19:28:20Z (GMT). No. of bitstreams: 1 Guenther_David_B_article_1997.pdf: 1401946 bytes, checksum: f8bc6df0de488dd161bf2e80ac3e6521 (MD5) Previous issue date: 1997-08 en
dc.language.iso en en_CA
dc.publisher American Astronomical Society en_CA
dc.relation.uri http://dx.doi.org/10.1086/304367
dc.rights Article is made available in accordance with the publisher’s policy and is subject to copyright law. Please refer to the publisher’s site. Any re-use of this article is to be in accordance with the publisher’s copyright policy. This posting is in no way granting any permission for re-use to the reader/user.
dc.subject.lcsh Sun -- Internal structure
dc.subject.lcsh Sun -- Evolution
dc.subject.lcsh Solar oscillations
dc.subject.lcsh Solar neutrinos
dc.title Seismic tests of the Sun's interior structure, composition, and age, and implications for solar neutrinos en_CA
dc.type Text en_CA
dcterms.bibliographicCitation Astrophysical Journal 484(2), 937-959. (1997) en_CA
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Article is made available in accordance with the publisher’s policy and is subject to copyright law. Please refer to the publisher’s site. Any re-use of this article is to be in accordance with the publisher’s copyright policy. This posting is in no way granting any permission for re-use to the reader/user.
 
Published Version: http://dx.doi.org/10.1086/304367
 
 

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