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Related papers: Asymmetries of Solar p-mode Line Profiles

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The asymmetries of solar p-mode lines provide important diagnostic clues as to the nature and location of the source of mode excitation. At the same time, they can also be responsible for systematic errors in the determination of mode…

Astrophysics · Physics 2007-05-23 C. S. Rosenthal

The observed solar p-mode velocity power spectra are compared with theoretically calculated power spectra over a range of mode degree and frequency. The shape of the theoretical power spectra depends on the depth of acoustic sources…

Astrophysics · Physics 2009-10-30 Pawan Kumar , Sarbani Basu

In a power spectrum of the Sun's acoustic waves, the p modes have distinctly skewed frequency profiles. Furthermore, the asymmetry is observed to have the opposite sign in power spectra made from line-of-sight velocity and continuum…

Solar and Stellar Astrophysics · Physics 2011-12-21 Bradley W. Hindman

The sense of line asymmetry of solar p-modes in the intensity power spectra is observed to be opposite of that seen in the velocity power spectra. Theoretical calculations provide a good understanding and fit to the observed velocity power…

Astrophysics · Physics 2009-10-30 Pawan Kumar , Sarbani Basu

Oscillation properties are usually measured by fitting symmetric Lorentzian profiles to the power spectra of Sun-like stars. However the line profiles of solar oscillations have been observed to be asymmetrical for the Sun. The physical…

Solar and Stellar Astrophysics · Physics 2018-05-02 O. Benomar , Mjo. Goupil , K. Belkacem , T. Appourchaux , M. B. Nielsen , M. Bazot , L. Gizon , S. Hanasoge , K. R. Sreenivasan , B. Marchand

Theoretically calculated power spectra are compares with observed solar p-mode velocity power spectra over a range of mode degree and frequency. The depth for the sources responsible for exciting p-modes of frequency 2.0 mHz is determined…

Astrophysics · Physics 2009-10-31 Pawan Kumar , Sarbani Basu

The solar acoustic p-mode line profiles are asymmetric. Velocity spectra have more power on the low-frequency sides, whereas intensity profiles show the opposite sense of asymmetry. Numerical simulations of the upper convection zone have…

Astrophysics · Physics 2009-11-07 Dali Georgobiani , Robert F. Stein , Aake Nordlund

In this paper, we aim to develop a predictive model for solar radial $p$-mode line profiles in the velocity spectrum. Unlike the approach favoured by prior studies, this model is not described by free parameters and we do not use fitting…

Solar and Stellar Astrophysics · Physics 2020-03-18 J. Philidet , K. Belkacem , R. Samadi , C. Barban , H. -G. Ludwig

The development of space-borne missions has significantly improved the quality of the measured spectra of solar-like oscillators. Their $p$-mode line profiles can now be resolved, and the asymmetries inferred for a variety of stars other…

Solar and Stellar Astrophysics · Physics 2021-01-04 J. Philidet , K. Belkacem , H. -G. Ludwig , R. Samadi , C. Barban

We seek to address whether solar-cycle frequency shifts of the Sun's low-l p modes `distort' the underlying shapes of the mode peaks, when those peaks are observed in power frequency spectra made from data spanning large fractions, or more,…

Astrophysics · Physics 2009-11-13 W. J. Chaplin , Y. Elsworth , R. New , T. Toutain

Despite the strong evidence that the peaks in the spectrum of solar oscillations are asymmetric, most determinations of mode frequencies have been based on fits of symmetric Lorentzian profiles to the Fourier or power spectra of oscillation…

Most helioseismic analyses are based on solar oscillations frequencies obtained by fitting symmetric peak profiles to the power spectra. However, it has now been demonstrated that the peaks are not symmetric. In this work we study the…

Astrophysics · Physics 2009-10-31 Sarbani Basu , H. M. Antia

The observed power spectrum of high-degree solar p-modes (l>200) shows discrepancies with the power spectrum predicted by the stochastic excitement and damping theory. In an attempt to explain these discrepancies, the present paper is…

Astrophysics · Physics 2009-11-11 B. M. Shergelashvili , S. Poedts

Using the local helioseismic technique of ring diagram we analyze the frequencies of high--degree f- and p-modes derived from both velocity and continuum intensity data observed by MDI. Fitting the spectra with asymmetric peak profiles, we…

Astrophysics · Physics 2011-02-11 S. C. Tripathy , H. M. Antia , Kiran Jain , F. Hill

This paper presents an analysis of observational data on the p-mode spectrum of the star alpha Cen B and a comparison with theoretical computations of the stochastic excitation and damping of the modes. We find that at frequencies > 4500…

Astrophysics · Physics 2011-02-11 W. J. Chaplin , G. Houdek , Y. Elsworth , R. New , T. R. Bedding , H. Kjeldsen

p-mode oscillations in solar-like stars are excited by the outer convection zone in these stars and reflected close to the surface. The p-modes are trapped inside an acoustic cavity, but the modes only stay trapped up to a given frequency…

Astrophysics · Physics 2009-11-13 C. Karoff

Recent studies have established that peaks in solar oscillation power spectra are not Lorentzian in shape, but have a distinct asymmetry. Fitting a symmetric Lorentzian profile to the peaks therefore produces a shift in frequency of the…

Solar p-mode frequencies vary with solar activity. It is important to take this into account when comparing the frequencies observed from epochs that span different regions of the solar cycle. We present details of how to correct observed…

Solar and Stellar Astrophysics · Physics 2015-05-13 A. -M. Broomhall , W. J. Chaplin , Y. Elsworth , S. T. Fletcher , R. New

Photospheric waves in sunspots moving radially outwards at speeds faster than the characteristic wave velocities have been recently detected. It has been suggested that they are the visual pattern of $p-$modes excited around 5 Mm beneath…

Solar and Stellar Astrophysics · Physics 2017-02-22 T. Felipe , E. Khomenko

Oscillations were observed across the whole solar disk using the Doppler shift and line depth of spectral lines from the CO molecule near 4666~nm with the National Solar Observatory's McMath/Pierce solar telescope. Power, coherence, and…

Solar and Stellar Astrophysics · Physics 2015-05-20 Matthew Penn , Tom Schad , Erin Cox
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