ALBERT

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: The Global Oscillation Network Group (GONG) project estimates the frequencies, amplitudes, and linewidths of more than 250,000 acoustic resonances of the sun from data sets lasting 36 days. The frequency resolution of a single data set is 0.321 microhertz. For frequencies averaged over the azimuthal order m, the median formal error is 0.044 microhertz, and the associated median fractional error is 1.6 x 10(-5). For a 3-year data set, the fractional error is expected to be 3 x 10(-6). The GONG m-averaged frequency measurements differ from other helioseismic data sets by 0.03 to 0.08 microhertz. The differences arise from a combination of systematic errors, random errors, and possible changes in solar structure.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hill -- Stark -- Stebbins -- Anderson -- Antia -- Brown -- Duvall Jr -- Haber -- Harvey -- Hathaway -- Howe -- Hubbard -- Jones -- Kennedy -- Korzennik -- Kosovichev -- Leibacher -- Libbrecht -- Pintar -- Rhodes Jr -- Schou -- Thompson -- Tomczyk -- Toner -- Toussaint -- Williams -- New York, N.Y. -- Science. 1996 May 31;272(5266):1292-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉F. Hill, E. R. Anderson, J. W. Harvey, R. P. Hubbard, J. R. Kennedy, J. W. Leibacher, J. A. Pintar, C. G. Toner, R. Toussaint, and W. E. Williams are with the National Solar Observatory, National Optical Astronomy Observatories (NOAO), Post Office Box 26732, Tucson, AZ 85726-6732, USA. P. B. Stark is with the Department of Statistics and Space Sciences Laboratory, University of California, Berkeley, CA 94720, USA. R. T. Stebbins and D. A. Haber are with JILA, University of Colorado, Boulder, CO 80309, USA. H. M. Antia is with the Tata Institute of Fundamental Research, Bombay, India. T. M. Brown and S. Tomczyk are with the High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO 80307, USA. T. L. Duvall is with the NASA Goddard Space Flight Center, Stanford University, Center for Space Science and Astrophysics (CSSA), Stanford, CA 94305, USA. D. H. Hathaway is with the NASA Marshall Space Flight Center, Mail Code ES82, Huntsville, AL 35812, USA. R. Howe and M. J. Thompson are with the Astronomy Unit, Queen Mary and Westfield College, London E1 4NS, UK. H. P. Jones is with the NASA Goddard Space Flight Center Southwest Station, NOAO, Tucson, AZ 85726, USA. S. G. Korzennik is with the Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA. A. G. Kosovichev and J. Schou are with Stanford University, CSSA, Stanford, CA 94305, USA. K. G. Libbrecht is with the California Institute of Technology, 264-33, Pasadena, CA 91125, USA. E. J. Rhodes is with the Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8662457" 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〉