Measurements of Frequencies of Solar Oscillations from the Mdi Medium-l Program

  title={Measurements of Frequencies of Solar Oscillations from the Mdi Medium-l Program},
  author={E. Rhodes and A. Kosovichev and J. Schou and P. Scherrer and J. Reiter},
  journal={Solar Physics},
Inversions of solar internal structure employ both the frequencies and the associated uncertainties of the solar oscillation modes as input parameters. In this paper we investigate how systematic errors in these input parameters may affect the resulting inferences of the sun's internal structure. Such systematic errors are likely to arise from inaccuracies in the theoretical models which are used to represent the spectral lines in the observational power spectra, from line blending, from… Expand

Figures from this paper

A Comparison of Solar p-Mode Parameters from MDI and Gong: Mode Frequencies and Structure Inversions
Helioseismic analysis of solar global oscillations allows investigation of the internal structure of the Sun. One important test of the reliability of the inferences from helioseismology is that theExpand
A method for the estimation of p-mode parameters from averaged solar oscillation power spectra
A new fitting methodology is presented which is equally well suited for the estimation of low-, medium-, and high-degree mode parameters from $m$-averaged solar oscillation power spectra of widelyExpand
Asymmetry and Frequencies of Low-Degree p-Modes and the Structure of the Sun's Core
An accurate determination of the frequencies of low-degree solar p-modes is an important task of helioseismology. Using 679 days of solar oscillation data observed in Doppler velocity and continuumExpand
Measuring the Sun's Eigenfrequencies from Velocity and Intensity Helioseismic Spectra: Asymmetrical Line Profile-fitting Formula
Solar eigenfrequencies are generally determined by fitting a Lorentzian to the spectral lines in the power spectrum. This assumes that the spectral line is symmetric. Recent observations from theExpand
Depth of excitation and reversal of asymmetry of low-ℓ solar p modes: a complementary analysis of BiSON and VIRGO/SPM data
We use the solutions to a simple, one-dimensional wave equation – which is intended to describe the essential elements of the solar resonant acoustic cavity – as formalistic models to which to fitExpand
Three helioseismic instruments on the Solar and Heliospheric Observatory have observed the Sun almost continuously since early 1996. This has led to detailed study of the biases induced by theExpand
Our Sun. IV. The Standard Model and Helioseismology: Consequences of Uncertainties in Input Physics and in Observed Solar Parameters
Helioseismology provides a powerful tool to explore the deep interior of the Sun. Measurements of solar interior quantities are provided with unprecedented accuracy: for example, the adiabatic soundExpand
Shortcomings of the Standard Solar Model
The SSM, invented in early nineteen sixties, remains a useful construction. There are now much larger number of its predictions that may be compared with observations than when it was firstExpand
Skew-symmetric solar p modes in low-l BiSON data
The p-mode oscillations of the Sun are manifestations of resonantly trapped acoustic waves propagating within its interior. The effective size of the resulting resonant cavity changes with theExpand
Observed and Predicted Ratios of the Horizontal and Vertical Components of the Solar p-Mode Velocity Eigenfunctions
We present evidence that the observed ratios of the horizontal and vertical components of the solar intermediate-degree p-mode velocity eigenfunctions closely match theoretical predictions of theseExpand


The medium-l program of the Michelson Doppler Imager instrument on board SOHO provides continuous observations of oscillation modes of angular degree, l, from 0 to ∽ 300. The data for the program areExpand
Asymmetries of solar oscillation line profiles
Asymmetries of the power spectral line profiles of solar global p-modes are detected in full-disk intensity observations of the Ca II K Fraunhofer line. The asymmetry is a strong function of temporalExpand
Constrained estimates of low-degree mode frequencies and the determination of the interior structure of the Sun
Low-degreep-modes penetrate to the solar centre and provide direct information about the core. However, the high observational accuracy that is required to resolve the details of the structure of theExpand
Asymmetries of Solar p-mode Line Profiles
Recent observations indicate that solar p-mode line profiles are not exactly Lorentzian but rather exhibit varying amounts of asymmetry about their peaks. We analyze p-mode line asymmetry by usingExpand
The Current State of Solar Modeling
Data from the GONG project and other helioseismic experiments reveal subtle errors in the models, such as an excess in sound speed just beneath the convection zone, which is plausible that the sound-speed differences reflect weak mixing in stellar interiors. Expand
The Solar Oscillations Investigation - Michelson Doppler Imager
The Solar Oscillations Investigation (SOI) uses the Michelson Doppler Imager (MDI) instrument to probe the interior of the Sun by measuring the photospheric manifestations of solar oscillations.Expand
The Solar Acoustic Spectrum and Eigenmode Parameters
The GONG m-averaged frequency measurements differ from other helioseismic data sets by 0.03 to 0.08 microhertz; the differences arise from a combination of systematic errors, random errors, and possible changes in solar structure. Expand
Acoustic waves in the Sun with frequencies above about 5.3 mHz can propagate in the chromosphere. We examine imaged solar intensity data for evidence of reflection of these waves in the upperExpand
On the location of the excitation of solar p-modes
We give the general expression for the power spectrum of oscillations nonlinearly excited by convection and we show how it simplifies for p-modes. The source term is described by a correlationExpand
Solar structure as revealed by 1 year LOWL data
We have used solar frequencies obtained from 1 year of observations with the LOWL instrument to investigate the radial stratiication of the Sun. Models which include the diiusion of helium and heavyExpand