ALBERT

Description: The way in which turbulent fluxes are usually represented in computations of large-scale flow in the convection zones of the sun and other stars is briefly described. A model of an ensemble of eddies that is capable of generalization to circumstances more complicated than the usual essentially spherically symmetrical convection zone is outlined. Generalization usually requires the introduction of new postulates, and, in so doing, also lays bare some of the assumptions, often implicit, in the usual mixing-length formalisms.

Description: The way in which turbulent fluxes are usually represented in computations of large-scale flow in the convection zones of the sun and other stars is briefly described. A model of an ensemble of eddies that is capable of generalization to circumstances more complicated than the usual essentially spherically symmetrical convection zone is outlined. Generalization usually requires the introduction of new postulates, and, in so doing, also lays bare some of the assumptions, often implicit, in the usual mixing-length formalisms.

Description: The way in which turbulent fluxes are usually represented in computations of large-scale flow in the convection zones of the sun and other stars is briefly described. A model of an ensemble of eddies that is capable of generalization to circumstances more complicated than the usual essentially spherically symmetrical convection zone is outlined. Generalization usually requires the introduction of new postulates, and, in so doing, also lays bare some of the assumptions, often implicit, in the usual mixing-length formalisms.

Description: Data from the Global Oscillation Network Group (GONG) project and other helioseismic experiments provide a test for models of stellar interiors and for the thermodynamic and radiative properties, on which the models depend, of matter under the extreme conditions found in the sun. Current models are in agreement with the helioseismic inferences, which suggests, for example, that the disagreement between the predicted and observed fluxes of neutrinos from the sun is not caused by errors in the models. However, the GONG data reveal subtle errors in the models, such as an excess in sound speed just beneath the convection zone. These discrepancies indicate effects that have so far not been correctly accounted for; for example, it is plausible that the sound-speed differences reflect weak mixing in stellar interiors, of potential importance to the overall evolution of stars and ultimately to estimates of the age of the galaxy based on stellar evolution calculations.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Christensen-Dalsgaard -- Dappen -- Ajukov -- Anderson -- Antia -- Basu -- Baturin -- Berthomieu -- Chaboyer -- Chitre -- Cox -- Demarque -- Donatowicz -- Dziembowski -- Gabriel -- Gough -- Guenther -- Guzik -- Harvey -- Hill -- Houdek -- Iglesias -- Kosovichev -- Leibacher -- Morel -- Proffitt -- Provost -- Reiter -- Rhodes Jr -- Rogers -- Roxburgh -- Thompson -- Ulrich -- New York, N.Y. -- Science. 1996 May 31;272(5266):1286-92.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉J. Christensen-Dalsgaard and S. Basu are with Theoretical Astrophysics Center and Institute of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark. W. Dappen and E. J. Rhodes Jr. are with the Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA. S. V. Ajukov is with the Sternberg Astronomical Institute, Moscow, Russia. E. R. Anderson, J. W. Harvey, F. Hill, and J. W. Leibacher are with the National Solar Observatory, National Optical Astronomy Observatories, Tucson, AZ 85726, USA. H. M. Antia and S. M. Chitre are with the Tata Institute of Fundamental Research, Bombay, India. V. A. Baturin, I. W. Roxburgh, and M. J. Thompson are with the Astronomy Unit, Queen Mary and Westfield College, London E1 4NS, UK. G. Berthomieu, P. Morel, and J. Provost are with the Observatoire de la Cote d'Azur, Nice, France. B. Chaboyer is with CITA, University of Toronto, Toronto, Canada. A. N. Cox and J. A. Guzik are with Los Alamos National Laboratory, Los Alamos, NM 87545, USA. P. Demarque is with the Department of Astronomy, Yale University, New Haven, CT 06520, USA. J. Donatowicz and G. Houdek are with the Institut fur Astronomie, Universitat Wien, Vienna, Austria. W. A. Dziembowski is with the Copernicus Center, Warsaw, Poland. M. Gabriel is with the Institut d'Astrophysique, Universite de Liege, Liege, Belgium. D. O. Gough is with the Institute of Astronomy, University of Cambridge, Cambridge, UK. D. B. Guenther is with the Department of Astronomy and Physics, Saint Mary's University, Halifax, Nova Scotia, Canada. C. A. Iglesias and F. J. Rogers are with the Lawrence Livermore National Laboratory, Livermore, CA 94550, USA. A. G. Kosovichev is with Center for Space Science and Astrophysics, Stanford University, Stanford, CA 94305, USA. C. R. Proffitt is with Computer Sciences Corporation, Goddard Space Flight Center, Greenbelt, MD 20771, USA. J. Reiter is with the Mathematisches Institut, Technische Universitat Munchen, Munich, Germany. R. K. Ulrich is with the Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8662456" target="_blank"〉PubMed〈/a〉

Description: Helioseismology is probing the interior structure and dynamics of the sun with ever-increasing precision, providing a well-calibrated laboratory in which physical processes can be studied under conditions that are unattainable on Earth. Nearly 10 million resonant modes of oscillation are observable in the solar atmosphere, and their frequencies need to be known with great accuracy in order to gauge the sun's interior. The advent of nearly continuous imaged observations from the complementary ground-based Global Oscillation Network Group (GONG) observatories and the space-based Solar and Heliospheric Observatory instruments augurs a new era of discovery. The flow of early results from GONG resolves some issues and raises a number of theoretical questions whose answers are required for understanding how a seemingly ordinary star actually operates.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gough -- Leibacher -- Scherrer -- Toomre -- New York, N.Y. -- Science. 1996 May 31;272(5266):1281-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉D. O. Gough is with the Institute of Astronomy, University of Cambridge, Cambridge, CB3 OHA UK. J. W. Leibacher is with the National Solar Observatory, Tucson, AZ, USA. P. H. Scherrer is with the Department of Physics, Stanford University, Stanford, CA, USA. J. Toomre is with JILA, University of Colorado, Boulder, CO, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8662454" target="_blank"〉PubMed〈/a〉

Description: Global Oscillation Network Group data reveal that the internal structure of the sun can be well represented by a calibrated standard model. However, immediately beneath the convection zone and at the edge of the energy-generating core, the sound-speed variation is somewhat smoother in the sun than it is in the model. This could be a consequence of chemical inhomogeneity that is too severe in the model, perhaps owing to inaccurate modeling of gravitational settling or to neglected macroscopic motion that may be present in the sun. Accurate knowledge of the sun's structure enables inferences to be made about the physics that controls the sun; for example, through the opacity, the equation of state, or wave motion. Those inferences can then be used elsewhere in astrophysics.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gough -- Kosovichev -- Toomre -- Anderson -- Antia -- Basu -- Chaboyer -- Chitre -- Christensen-Dalsgaard -- Dziembowski -- Eff-Darwich -- Elliott -- Giles -- Goode -- Guzik -- Harvey -- Hill -- Leibacher -- Monteiro -- Richard -- Sekii -- Shibahashi -- Takata -- Thompson -- Vauclair -- Vorontsov -- New York, N.Y. -- Science. 1996 May 31;272(5266):1296-300.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉D. O. Gough, J. R. Elliott, and T. Sekii are with the Institute of Astronomy, University of Cambridge, CB3 0HA, UK. A. G. Kosovichev and P. R. Giles are with HEPL, Stanford University, Stanford, CA, USA. J. Toomre is at JILA, University of Colorado, Boulder, CO, USA. E. Anderson, J. W. Harvey, F. Hill, and J. W. Leibacher are at the National Solar Observatory, Tucson, AZ, USA. H. M. Antia and S. M. Chitre are at the Tata Institute for Fundamental Research, Bombay, India. S. Basu and J. Christensen-Dalsgaard are at the Theoretical Astrophysics Centre, Aarhus University, Denmark. B. Chaboyer is at the Canadian Institute for Theoretical Astrophysics, Toronto, Canada. W. A. Dziembowski is at the Copernicus Astronomical Center, Warsaw, Poland. A. Eff-Darwich is at the Instituto Astrofisico de Canarias, Tenerife, Canary Islands. P. R. Goode is at the New Jersey Institute of Technology, Newark, NJ, USA. J. A. Guzik is at the Los Alamos National Laboratory, Los Alamos, NM, USA. M. J. P. F. G. Monteiro is at the University of Oporto, Postugal. O. Richard and S. Vauclair are at the Observatoire Midi-Pyrenees, Toulouse, France. H. Shibahashi and M. Takata are in the Department of Astronomy, University of Tokyo, Tokyo, Japan. M. J. Thompson and S. V. Vorontsov are at Queen Mary and Westfield College, University of London, London, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8662458" target="_blank"〉PubMed〈/a〉

Description: Splitting of the sun's global oscillation frequencies by large-scale flows can be used to investigate how rotation varies with radius and latitude within the solar interior. The nearly uninterrupted observations by the Global Oscillation Network Group (GONG) yield oscillation power spectra with high duty cycles and high signal-to-noise ratios. Frequency splittings derived from GONG observations confirm that the variation of rotation rate with latitude seen at the surface carries through much of the convection zone, at the base of which is an adjustment layer leading to latitudinally independent rotation at greater depths. A distinctive shear layer just below the surface is discernible at low to mid-latitudes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Thompson -- Toomre -- Anderson -- Antia -- Berthomieu -- Burtonclay -- Chitre -- Christensen-Dalsgaard -- Corbard -- DeRosa -- Genovese -- Gough -- Haber -- Harvey -- Hill -- Howe -- Korzennik -- Kosovichev -- Leibacher -- Pijpers -- Provost -- Rhodes Jr -- Schou -- Sekii -- Stark -- Wilson -- New York, N.Y. -- Science. 1996 May 31;272(5266):1300-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉M. J. Thompson and R. Howe are in the Astronomy Unit, Queen Mary and Westfield College, University of London, Mile End Road, London E1 4NS, UK. J. Toomre, M. DeRosa, and D. A. Haber are at the Joint Institute for Laboratory Astrophysics, University of Colorado, Boulder, CO 80309-0440, USA. E. R. Anderson, J. W. Harvey, F. Hill, and J. W. Leibacher are at the National Solar Observatory (NSO), National Optical Astronomy Observatories (NOAO), Post Office Box 26732, Tucson, AZ 85726-6732, USA. H. M. Antia and S. M. Chitre are at the Tata Institute of Fundamental Research, Bombay 400005, India. G. Berthomieu, T. Corbard, and J. Provost are at the Observatoire de la Cote d'Azur, 06304 Nice Cedex 4, France. D. Burtonclay and P. R. Wilson are in the School of Mathematics, University of Sydney, Sydney, NSW 2006, Australia. J. Christensen-Dalsgaard and F. P. Pijpers are at the Theoretical Astrophysics Center, Aarhus University, DK-8000 Aarhus C, Denmark. C. R. Genovese is in the Department of Statistics, Carnegie Mellon University, Pittsburgh, PA 15213, USA. D. O. Gough and T. Sekii are in the Institute of Astronomy, University of Cambridge, Cambridge CB3 0HA, UK. S. G. Korzennik is at the Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA. A. G. Kosovichev and J. Schou are at Hansen Experimental Physics Laboratory Annex, Stanford University, Stanford, CA 94305-4085, USA. E. J. Rhodes Jr. is in the Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA. P. B. Stark is in the Department of Statistics, University of California, Berkeley, CA 94720-3860, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8662459" target="_blank"〉PubMed〈/a〉

Description: The way in which turbulent fluxes are usually represented in computations of large-scale flow in the convection zones of the sun and other stars is briefly described. A model of an ensemble of eddies that is capable of generalization to circumstances more complicated than the usual essentially spherically symmetrical convection zone is outlined. Generalization usually requires the introduction of new postulates, and, in so doing, also lays bare some of the assumptions, often implicit, in the usual mixing-length formalisms.

Description: The way in which turbulent fluxes are usually represented in computations of large-scale flow in the convection zones of the sun and other stars is briefly described. A model of an ensemble of eddies that is capable of generalization to circumstances more complicated than the usual essentially spherically symmetrical convection zone is outlined. Generalization usually requires the introduction of new postulates, and, in so doing, also lays bare some of the assumptions, often implicit, in the usual mixing-length formalisms.

Description: The way in which turbulent fluxes are usually represented in computations of large-scale flow in the convection zones of the sun and other stars is briefly described. A model of an ensemble of eddies that is capable of generalization to circumstances more complicated than the usual essentially spherically symmetrical convection zone is outlined. Generalization usually requires the introduction of new postulates, and, in so doing, also lays bare some of the assumptions, often implicit, in the usual mixing-length formalisms.