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  • 1
    Electronic Resource
    Electronic Resource
    THE INTERNAL ROTATION OF THE SUN (2003)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Astronomy and Astrophysics 41 (2003), S. 599-643 
    Details
    ISSN: 0066-4146
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Physics
    Notes: Helioseismology has transformed our knowledge of the Sun's rotation. Earlier studies revealed the Sun's surface rotation, but now a detailed observational picture has been built up of the internal rotation of our nearest star. Unlike the predictions of stellar-evolution models, the radiative interior is found to rotate roughly uniformly. The rotation within the convection zone is also very different from prior expectations, which had been that the rotation rate would depend primarily on the distance from the rotation axis. Layers of rotational shear have been discovered at the base of the convection zone and in the subphotospheric layers. Studies of the time variation of rotation have uncovered zonal-flow bands, extending through a substantial fraction of the convection zone, which migrate over the course of the solar cycle, and there are hints of other temporal variations and of a jet-like structure. At the same time, building on earlier work with mean-field models, researchers have made great progress in supercomputer simulations of the intricate interplay between turbulent convection and rotation in the Sun's interior. Such studies are beginning to transform our understanding of how rotation organizes itself in a stellar interior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.astro.41.011802.094848
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  • 2
    Electronic Resource
    Electronic Resource
    Astronomy Where are Procyon's quakes? (2004)
    [s.l.] : Nature Publishing Group
    Nature 430 (2004), S. 29-30 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] More than a quarter of a century ago the Sun was found to be a variable star, the velocity of its surface gas varying with periods of around five minutes. A breakthrough came in 1979 with the first detection of large-scale oscillations on the solar surface. These oscillations, or ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/430029a
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  • 3
    Electronic Resource
    Electronic Resource
    Solar oscillations and the equation of state (1992)
    Springer
    The astronomy and astrophysics review 4 (1992), S. 267-361 
    Details
    ISSN: 1432-0754
    Keywords: Solar structure ; Solar oscillations ; Thermodynamics of stellar interiors ; Helioseismology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Accurate measurements of observed frequencies of solar oscillations are providing a wealth of data on the properties of the solar interior. The frequencies depend on solar structure, and on the properties of the plasma in the Sun. Here we consider in particular the dependence on the thermodynamic state. From an analysis of the equations of stellar structure, and the relevant aspects of the properties of the oscillations, we argue that in the convection zone one can isolate information about the equation of state which is relatively unaffected by other uncertainties in the physics of the solar interior. We review the different treatments that have been used to describe the thermodynamics of stellar plasmas. Through application of several of these to the computation of models of the solar envelope we demonstrate that the sensitivity of the observed frequencies is in fact sufficient to distinguish even quite subtle features of the physics of solar matter. This opens up the possibility of using the Sun as a laboratory for statistical mechanics, under conditions that are out of reach in a terrestrial laboratory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00872687
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  • 4
    Electronic Resource
    Electronic Resource
    Seismology makes waves (1993)
    [s.l.] : Nature Publishing Group
    Nature 362 (1993), S. 409-410 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] JUST as earth scientists can investigate the Earth's interior with seismology, so solar physicists can study the Sun's interior. But whereas terrestrial seismic waves are generated by isolated earthquakes (or explosions), solar oscillations arise from persistent gentle and random prodding by ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/362409a0
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  • 5
    Electronic Resource
    Electronic Resource
    Nature; 376.1995, 6542, S.641-642 (1995)
    [s.l.] : Nature Publishing Group
    Nature 376 (1995), S. 641-642 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] THE rotation rate of stars appears to decrease with increasing age, particularly for stars of relatively low mass such as the Sun1. Stars are apparently born with rapid rotation, as a result of their formation through contraction of an initially slowly rotating gas cloud. The subsequent loss of ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/376641a0
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  • 6
    Electronic Resource
    Electronic Resource
    Detection of the Lower Boundary of Stellar Convective Envelopes from Seismic Data (1998)
    Springer
    Astrophysics and space science 261 (1998), S. 41-42 
    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:1002076921732
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  • 7
    Electronic Resource
    Electronic Resource
    Asteroseismology (1998)
    Springer
    Astrophysics and space science 261 (1998), S. 1-12 
    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:1002067301259
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  • 8
    Electronic Resource
    Electronic Resource
    The ‘Standard’ Sun Modelling and Helioseismology (1998)
    Springer
    Space science reviews 85 (1998), S. 19-36 
    Details
    ISSN: 1572-9672
    Keywords: Sun ; structure — Sun ; composition — helioseismology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The ‘standard’ solar model is based on a number of simplifying assumptions and depends on knowledge of the physical properties of matter in the Sun. Given these assumptions, the constraint that the model have the observed surface luminosity provides an estimate of the initial solar helium abundance. From helioseismic analyses further information can be obtained about the present composition, including a fairly precise measure of the envelope helium abundance and an estimate of the hydrogen profile in the radiative interior. It must be emphasized, however, that these inferences may suffer from systematic error arising from incomplete knowledge about the equation of state and opacity of the solar interior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005116132024
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  • 9
    Electronic Resource
    Electronic Resource
    Radiative transfer and solar oscillations (1983)
    Springer
    Solar physics 82 (1983), S. 165-204 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We consider the atmospheric behaviour of solar oscillations in a model including a detailed, semi-empirical atmosphere. Equations of radial and non-radial oscillation, with consistent treatment of the radiation field, are derived. These equations are solved in the radial, grey case; the results show that departure from the Eddington approximation has little effect on the properties of the oscillations. Preliminary results are presented for the non-radial case, indicating substantial deviations from the Eddington approximation when the optical thickness across a horizontal wavelength is of the order of or less than unity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00145558
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  • 10
    Electronic Resource
    Electronic Resource
    Stellar 5 min oscillations (1983)
    Springer
    Solar physics 82 (1983), S. 469-486 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Estimates are given for the amplitudes of stochastically excited oscillations in Main Sequence stars and cool giants; these were obtained using the equipartition between convective and pulsational energy which was originally proposed by Goldreich and Keeley. The amplitudes of both velocity and luminosity perturbation generally increase with increasing mass along the Main Sequence as long as convection transports a major fraction of the total flux, and the amplitudes also increase with the age of the model. The 1.5 M ⊙ ZAMS model, of spectral type F0, has velocity amplitudes ten times larger than those found in the Sun. For very luminous red supergiants luminosity amplitudes of up to about 0 m .1 are predicted, in rough agreement with observations presented by Maeder.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00145588
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