Related papers: Solar Cycle Related Changes at the Base of the Con…
The frequencies of the solar acoustic oscillations vary over the activity cycle. The variations in other activity proxies are found to be well correlated with the variations in the acoustic frequencies. However, each proxy has a slightly…
We examine continuous measurements of the high-degree acoustic mode frequencies of the Sun covering the period from 2001 July to June 2014. These are obtained through the ring-diagram technique applied to the full-disk Doppler observations…
Small cyclic variations in the frequencies of acoustic modes are expected to be a common phenomenon in solar-like pulsators, as a result of stellar magnetic activity cycles. The frequency variations observed throughout the solar and stellar…
We have analysed the recently available GONG p-mode frequencies and splitting coefficients for a period of three and half years, including the rapidly rising phase of solar cycle 23. The analysis of mean frequency shift with different…
The latitudinal sound-speed structure of the Sun's convection zone gives insight into the physical processes occurring there, specifically the cellular convection and possibly the presence of magnetic fields. Using helioseismic data from…
Adiabatic oscillation frequencies of stellar models, computed with the standard mixing-length formulation for convection, increasingly deviate with radial order from observations in solar-like stars. Standard solar models overestimate…
We investigate the spatial and temporal variations of the high-degree mode frequencies calculated over localized regions of the Sun during the extended minimum phase between solar cycles 23 and 24. The frequency shifts measured relative to…
We study the variation of the frequency splitting coefficients describing the solar asphericity in both GONG and MDI data, and use these data to investigate temporal sound-speed variations as a function of both depth and latitude during the…
Frequencies of intermediate-degree f-modes of the Sun seem to indicate that the solar radius is smaller than what is normally used in constructing solar models. We investigate the possible consequences of an error in radius on results for…
Variations of frequency separations of low-degree p-modes are studied over the solar activity cycle. The separations studied are obtained from the frequencies of low-degree p-modes of the Global Oscillation Network Group (GONG). 10.7 cm…
Perturbation theory is used to calculate the frequency shift of acoustic modes of an homogeneous turbulent fluid and the frequency shifts of solar modes due to turbulent convection. For sound waves in a random flow, the fractional frequency…
High quality observations of the low-degree acoustic modes (p-modes) exist for almost two complete solar cycles using the solar spectrophotometer Mark-I, located at the Observatorio del Teide (Tenerife, Spain) and operating now as part of…
We present results on variation in rotation rate in the upper convection zone using data from GONG and MDI/SOHO covering a period of more than four years. We find that the first few odd-order splitting coefficients vary systematically with…
The structure of the surface layers of the Sun is changed by magnetic activity which, in turn, changes the eigenfrequencies of the acoustic modes. These frequency shifts have been observed both in low- and high-degree data, and are found to…
The observed splittings of solar oscillation frequencies can be employed to separate the effects of internal solar rotation and to estimate the contribution from a large-scale magnetic field or any latitude-dependent thermal perturbation…
Helioseismology has provided very detailed inferences about rotation of the solar interior. Within the convection zone the rotation rate roughly shares the latitudinal variation seen in the surface differential rotation. The transition to…
We present a formalism for investigating the interaction between pmode oscillations and convection by analyzing realistic, three-dimensional simulations of the near-surface layers of the solar convection zone. By choosing suitable…
We present a correlation analysis of GONG p-mode frequencies with nine solar activity indices for the period 1995 August to 1997 August. This study includes spherical harmonic degree in the range 2 to 150 and the frequency range of…
We investigate the variation in the mode parameters obtained from time series of length 9, 36, 72 and 108 days to understand the changes occurring on different time-scales. The regression analysis between frequency shifts and activity…
Solar-like oscillations are expected to be excited in stars of up to about 1.6 solar masses. Most of these stars will have convective cores during their Main-sequence evolution. At the edges of these convective cores there is a rapid…