Solar internal sound speed as inferred from combinedBiSON and
نویسندگان
چکیده
Observations of the Sun with the LOWL instrument provide a homogeneous set of solar p-mode frequencies from low to intermediate degree which allows one to determine the structure of much of the solar interior avoiding systematic errors that are introduced when diierent data sets are combined, i.e., principally the eeects of solar cycle changes on the frequencies. Unfortunately, the LOWL data set contains very few of the lowest-degree modes, which are essential for determining reliably the structure of the solar core { in addition, these lowest-degree data have fairly large associated uncertainties. However, observations made by the Birmingham Solar-Oscillations Network (BiSON) in integrated sunlight provide high-accuracy measurements of a large number of low-degree modes. In this paper we demonstrate that the low-degree mode set of the LOWL data can be successfully combined with the more accurate BiSON data, provided the observations are contemporaneous for those frequencies where the solar-cycle-induced eeects are important. We show that this leads to a factor-of-two decrease in the error on the inferred sound speed in the solar core. We nd that the solar sound speed is higher than in solar models for r < 0:2R. The density of the solar core is, however, lower than that in solar models.
منابع مشابه
Solar internal sound speed as inferred from combinedBiSON and LOWL oscillation
Observations of the Sun with the LOWL instrument provide a homogeneous set of solar p-mode frequencies from low to intermediate degree which allows one to determine the structure of much of the solar interior avoiding systematic errors that are introduced when diierent data sets are combined, i.e., principally the eeects of solar cycle changes on the frequencies. Unfortunately, the LOWL data se...
متن کاملSolar internal sound speed as inferred from combined BiSON and LOWL oscillation frequencies
Observations of the Sun with the LOWL instrument provide a homogeneous set of solar p-mode frequencies from low to intermediate degree which allows one to determine the structure of much of the solar interior avoiding systematic errors that are introduced when different data sets are combined, i.e., principally the effects of solar cycle changes on the frequencies. Unfortunately, the LOWL data ...
متن کاملImaging the Solar Tachocline by Time-Distance Helioseismology
The solar tachocline at the bottom of the convection zone is an important region for the dynamics of the Sun and the solar dynamo. In this region, the sound speed inferred by global helioseismology exhibits a bump of approximately 0.4% relative to the standard solar model. Global helioseismology does not provide any information on possible latitudinal variations or asymmetries between the North...
متن کاملAspects of the solar tachocline
The splitting of the frequencies of p-modemultiplets enables information to be gained about the internal rotation of the sun. Such data have revealed a transition at the base of the convection zone from differential rotation similar to that observed at the surface to almost solid-body rotation in the radiative interior. This transition region, known as the tachocline, has been found to be relat...
متن کاملSeismic inversions for temperature and chemical composition profiles in the solar interior
The primary inversion of the accurately measured frequencies of solar oscillations determines the mechanical properties of the Sun, i.e., the sound speed and density as a function of solar radius. In order to infer the temperature and hydrogen abundance profiles inside the Sun, it becomes necessary to use, in addition, the equations of thermal equilibrium along with the input physics, such as o...
متن کامل