Results 161 to 170 of about 1,537 (202)
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Science, 1991
Globally coherent oscillation modes were discovered in the sun about a decade ago, providing a unique seismological probe of the solar interior. Current observations detect modes that are phase-coherent for up to 1 year, with surface velocity amplitudes as low as 2 millimeters per second, and thousands of mode frequencies have been ...
Libbrecht, K. G., Woodard, M. F.
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Globally coherent oscillation modes were discovered in the sun about a decade ago, providing a unique seismological probe of the solar interior. Current observations detect modes that are phase-coherent for up to 1 year, with surface velocity amplitudes as low as 2 millimeters per second, and thousands of mode frequencies have been ...
Libbrecht, K. G., Woodard, M. F.
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EAS Publications Series, 2007
Helioseismic inferences have demonstrated very clearly the importance of including element diffusion and settling in solar modelling: models incorporating these processes are in substantially better agreement with the inferred solar sound speed than are models that neglect them.
Christensen-Dalsgaard, Jørgen; id_orcid 0000-0001-5137-0966 +1 more
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Helioseismic inferences have demonstrated very clearly the importance of including element diffusion and settling in solar modelling: models incorporating these processes are in substantially better agreement with the inferred solar sound speed than are models that neglect them.
Christensen-Dalsgaard, Jørgen; id_orcid 0000-0001-5137-0966 +1 more
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Probing sunspots with two-skip time–distance helioseismology [PDF]
Astronomy and Astrophysics, 2018 Context. Previous helioseismology of sunspots has been sensitive to both the structural and magnetic aspects of sunspot structure.Aims. We aim to develop a technique that is insensitive to the magnetic component so the two aspects can be more readily ...
Paul Stuart Cally +2 more
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An Introduction to Helioseismology
2000In no other case has stellar variability been honed to such a sharp astrophysical tool as for the Sun. The extreme richness of oscillation data available for the Sun, as a result of its proximity and the nature of the excitation processes responsible for the oscillations, provides us with a scalpel which allows us to dissect in minute detail, layer by ...
Christensen-Dalsgaard, J.; id_orcid 0000-0001-5137-0966 +3 more
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Perspectives in Helioseismology
Science, 1996Helioseismology 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
, Gough +3 more
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Laser heterodyne spectrometer for helioseismology
Applied Optics, 1986The technique of laser heterodyne spectroscopy has been applied to the measurement of solar oscillations. Coherent mixing of solar radiation with the output of a frequency-stabilized CO2 laser permits the measurement of fully resolved profiles of solar absorption lines with high spectral purity and excellent frequency stability. This technique has been
D A, Glenar +4 more
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Solar Models and Helioseismology
2000Helioseismic results put very important constraints on structure of the solar models, which can not be reachable by another way. These constraints lead toward what we should do to obtain a solar model in good agreement with the Sun. In this connection, diffusion of chemical elements took its indispensable part in the standard solar models.
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Advances in Space Research, 1994
Abstract The prospect of a future manned lunar base presents an interesting challenge for helioseismology-a field in which observations have been obtained from the Earth's surface, from near-earth satellites, and from interplanetary space-craft.
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Abstract The prospect of a future manned lunar base presents an interesting challenge for helioseismology-a field in which observations have been obtained from the Earth's surface, from near-earth satellites, and from interplanetary space-craft.
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Helioseismology Observations by Solar-A satellite
Advances in Space Research, 1991Helioseismological observations that can be made by using the aspect telescope on board the Solar-A satellite are discussed.
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Helioseismology and the solar interior dynamics
Journal of Astrophysics and Astronomy, 2000AbstractThe inversion of helioseismic modes leads to the sound velocity inside the Sun with a precision of about 0.1 per cent. Comparisons of solar models with the “seismic sun” represent powerful tools to test the physics: depth of the convection zone, equation of state, opacities, element diffusion processes and mixing inside the radiative zone.
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