scholarly journals Seismic Solar Models and the Neutrino Problem

1998 ◽  
Vol 185 ◽  
pp. 21-24
Author(s):  
M. Takata ◽  
H. Shibahashi
Keyword(s):  
Stellar Evolution ◽  
Sound Speed ◽  
Convection Zone ◽  
Solar Model ◽  
The Sun ◽  
Solar Neutrino Problem ◽  
Sound Speed Profile ◽  
The Core ◽  
Neutrino Fluxes ◽  
Capture Rates

We determine the structure of the solar radiative zone with the imposition of the sound speed profile and the depth of the convection zone obtained from helioseismic analysis. We discuss the neutrino fluxes and capture rates using the resultant seismic solar model. We find that the seismic solar model cannot resolve the solar neutrino problem. The hydrogen and helium profiles of the Sun are obtained as a part of the solutions. We find that hydrogen is reduced in the core as expected in the theory of stellar evolution.

Making a seismic solar model and an estimate of the neutrino fluxes

1997 ◽  
Vol 181 ◽  
pp. 167-174
Author(s):  
H. Shibahashi ◽  
M. Takata
Keyword(s):  
Sound Speed ◽  
Stellar Structure ◽  
Solar Model ◽  
The Sun ◽  
Speed Profile ◽  
Standard Solar Model ◽  
Sound Speed Profile ◽  
History Of ◽  
Basic Equations ◽  
Neutrino Fluxes

We present a method of making a solar model based on the helioseismic data. We first invert the observed eigenfrequencies to determine the sound speed profile, and then solve the basic equations governing the stellar structure with the imposition of the determined sound-speed profile. This approach is different from that of the standard solar model in the sense that the ‘seismic’ solar model is a snapshot model of the sun constructed without any assumption about the history of the sun. We invert the data obtained at the South Pole by the Bartol/NSO/NASA group along with BISON, HLH, and LOWL data. Finally we estimate the neutrino fluxes of the seismic model.

scholarly journals Helioseismology: the Sun as a Strongly-Constrained, Weakly-Coupled Plasma

1994 ◽  
Vol 147 ◽  
pp. 368-393 ◽  
Author(s):  
W. Däppen
Keyword(s):  
Equation Of State ◽  
Sound Speed ◽  
Convection Zone ◽  
Solar Interior ◽  
Heavy Elements ◽  
The Sun ◽  
Speed Profile ◽  
Sound Speed Profile ◽  
Specific Entropy ◽  
Weakly Coupled

AbstractAccurate measurements of observed frequencies of solar oscillations are providing a wealth of data on the properties of the solar interior. The frequencies depend on the solar structure, and on the properties of the plasma in the Sun. Except in the very outer layers, the stratification of the convection zone is almost adiabatic. There, the sound-speed profile is governed principally by the specific entropy, the (homogenous) chemical composition and the equation of state. It is therefore essentially independent of the uncertainties in the radiative opacities. The sensitivity of the observed frequencies is such that it enables to distinguish rather subtle features of the equation of state. An example is the signature of the heavy elements in the equation of state. This opens the possibility to use the Sun as a laboratory for thermodynamic properties.

scholarly journals The Toroidal Magnetic Field inside the Sun

1991 ◽  
Vol 130 ◽  
pp. 187-189
Author(s):  
V.N. Krivodubskij ◽  
A.E. Dudorov ◽  
A.A. Ruzmaikin ◽  
T.V. Ruzmaikina
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Convection Zone ◽  
The Sun ◽  
Poloidal Magnetic Field ◽  
Radial Gradient ◽  
The Core ◽  
Large Scale Magnetic Field ◽  
Magnetic Buoyancy ◽  
The Magnetic Field

Analysis of the fine structure of the solar oscillations has enabled us to determine the internal rotation of the Sun and to estimate the magnitude of the large-scale magnetic field inside the Sun. According to the data of Duvall et al. (1984), the core of the Sun rotates about twice as fast as the solar surface. Recently Dziembowski et al. (1989) have showed that there is a sharp radial gradient in the Sun’s rotation at the base of the convection zone, near the boundary with the radiative interior. It seems to us that the sharp radial gradients of the angular velocity near the core of the Sun and at the base of the convection zone, acting on the relict poloidal magnetic field Br, must excite an intense toroidal field Bф, that can compensate for the loss of the magnetic field due to magnetic buoyancy.

scholarly journals Helioseismology and the Solar Neutrino Problem

1998 ◽  
Vol 185 ◽  
pp. 41-42
Author(s):  
H. M. Antia ◽  
S. M. Chitre
Keyword(s):  
Solar Neutrino ◽  
Sound Speed ◽  
Nuclear Energy ◽  
Solar Interior ◽  
Density Profiles ◽  
Solar Neutrino Problem ◽  
Composition Profiles ◽  
Neutrino Fluxes ◽  
Solar Material ◽  
Seismic Models

The precisely measured frequencies of solar oscillations provide us with a unique tool to probe the solar interior with sufficient accuracy. These frequencies are principally determined by the dynamical quantities like sound speed, density or the adiabatic index of the solar material and a primary inversion of the observed frequencies yields the sound speed and density profiles inside the Sun (Gough et al. 1996). The equations of thermal equilibrium enable us to determine the temperature and chemical composition profiles, but for this additional prescriptions regarding the input physics (i.e., opacities, equation of state and nuclear energy generation rate) are required (Shibahashi 1993; Antia & Chitre 1995; Shibahashi & Takata 1996; Kosovichev 1996). This information in turn can be used to calculate the neutrino fluxes, and the seismic models can thus be used to explore the possibility of an astrophysical solution to the solar neutrino problem (Roxburgh 1996; Antia & Chitre 1997).

Solar Metal Abundance Inferred from Helioseismology

2001 ◽  
Vol 203 ◽  
pp. 43-45
Author(s):  
M. Takata ◽  
H. Shibahashi
Keyword(s):  
Sound Speed ◽  
Heavy Element ◽  
Convection Zone ◽  
Element Abundance ◽  
Solar Model ◽  
Solar Oscillation ◽  
Solar Structure ◽  
Metal Abundance ◽  
Basic Equations ◽  
Oscillation Frequencies

In our previous work (Takata & Shibahashi 1998), we constructed a solar model called the seismic solar model, which has the consistent profile of sound speed as well as the consistent depth of the convection zone with helioseismology. The profile of the heavy element abundance, however, had to be assumed to be constant for feasibility. Here we try to constrain the distribution of the heavy element abundance as well by the solar oscillation frequencies, adopting all of the basic equations which govern the solar structure.

Helioseismology and the Solar Interior Dynamics

2000 ◽  
Vol 179 ◽  
pp. 323-329
Author(s):  
S. Vauclair
Keyword(s):  
Equation Of State ◽  
Convection Zone ◽  
Diffusion Processes ◽  
Solar Rotation ◽  
Solar Interior ◽  
The Other ◽  
The Sun ◽  
Helium 3 ◽  
Radiative Zone ◽  
Neutrino Fluxes

AbstractThe 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. We now have evidence that microscopic diffusion (element segregation) does occur below the convection zone, leading to a mild helium depletion in the solar outer layers. Meanwhile this process must be slowed down by some macroscopic effect, presumably rotation-induced mixing. The same mixing is also responsible for the observed lithium depletion. On the other hand, the observations of beryllium and helium 3 impose specific constraints on the depth of this mildly mixed zone. Helioseismology also gives information on the internal solar rotation: while differential rotation exists in the convection zone, solid rotation prevails in the radiative zone, and the transition layer (the so-called “tachocline”) is very small. These effects are discussed, together with the astrophysical constraints on the solar neutrino fluxes.

Solar Model with Metal-enhanced Convective Envelope

2001 ◽  
Vol 203 ◽  
pp. 46-49
Author(s):  
J. Y. Yang ◽  
Y. Li ◽  
H. Y. Xu
Keyword(s):  
Sound Speed ◽  
Convection Zone ◽  
Heavy Elements ◽  
Solar Model ◽  
Helium Abundance ◽  
Convective Envelope ◽  
Deep Interior

Solar model with moderate enrichment of heavy elements in the convective envelope is investigated using the up-to-date input physics. It is found that metal enriched model can result in adequate depth of the convection zone and appropriate surface helium abundance, and the agreement between the calculated and observed p-mode frequencies are also improved. The sound speed of our model is worse than SSM and DSM in deep interior, but is better in the base of convection zone.

scholarly journals The evolution of ‘the moment of inertia’ of stars

2008 ◽  
Vol 4 (S252) ◽  
pp. 117-118 ◽  
Author(s):  
Y.-C. Kim ◽  
S. Barnes
Keyword(s):  
Stellar Evolution ◽  
Convection Zone ◽  
Open Cluster ◽  
Rotation Period ◽  
Stellar Mass ◽  
Turnover Time ◽  
Moment Of Inertia ◽  
The Core ◽  
Rotation Periods ◽  
The Moment

AbstractObservations of the rotation periods of cool open cluster stars display a distinctive dichotomy when plotted against stellar mass/color. Other measures of stellar activity are also known to be dependent on stellar mass and structure, especially the onset and characteristics of convection zones. One proposal for understanding the observed rotation period dichotomy suggested dependencies on the moment of inertia of either the whole star or that of only the outer convection zone (Barnes 2003).The moment of inertia of stars with the mass between 0.1Msun and 3.0Msun have been calculated using a version of Yale Stellar evolution code (aka YREC). Each star has been evolved from stellar birthline to the onset of the core He burning. For easy comparison to observations, we have calculated the isochrones of these quantities as well as the convective turnover time, of interest to the activity community.

Perspectives on the Interior of the Sun

2000 ◽  
Vol 179 ◽  
pp. 331-337
Author(s):  
S. M. Chitre
Keyword(s):  
Particle Physics ◽  
Solar Model ◽  
The Sun ◽  
Standard Solar Model ◽  
Physical Conditions ◽  
Viable Solution ◽  
Internal Constitution ◽  
Structure Equations ◽  
Neutrino Fluxes ◽  
Oscillation Frequencies

AbstractThe interior of the Sun is not directly accessible to observations. Nonetheless, it is possible to infer the physical conditions inside the Sun with the help of structure equations governing its equilibrium and with the powerful observational tools provided by the neutrino fluxes and oscillation frequencies. The helioseismic data show that the internal constitution of the Sun can be adequately represented by a standard solar model. It turns out that a cooler solar core is not a viable solution for the measured deficit of neutrino fluxes, and the resolution of the solar neutrino puzzle should be sought in the realm of particle physics.

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