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Solar twins have been a focus of attention for more than a decade, because their structure is extremely close to that of the Sun. Today, thanks to high-precision spectrometers, it is possible to use asteroseismology to probe their…

Sub-photospheric acoustic resonators allow for the formation of standing p-mode oscillations by reflecting acoustic waves with frequencies below the acoustic cut-off frequency. We employ the Klein-Gordon equation with a piecewise acoustic…

Solar and Stellar Astrophysics · Physics 2024-08-22 Dmitrii Y. Kolotkov , Anne-Marie Broomhall , Amir Hasanzadeh

We have studied solar cycle changes in the large frequency separations that can be observed in Birmingham Solar Oscillations Network (BiSON) data. The large frequency separation is often one of the first outputs from asteroseismic studies…

Solar and Stellar Astrophysics · Physics 2015-05-27 A. -M. Broomhall , W. J. Chaplin , Y. Elsworth , R. New

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

Aims. With the Solar Optical Telescope on Hinode, we investigate the basic properties of high-degree solar oscillations observed at two levels in the solar atmosphere, in the G-band (formed in the photosphere) and in the Ca II H line…

Astrophysics · Physics 2009-11-13 U. Mitra-Kraev , A. G. Kosovichev , T. Sekii

We investigate the parameters of global solar p-mode oscillations, namely damping width $\Gamma$, amplitude $A$, mean squared velocity $\langle v^2\rangle$, energy $E$, and energy supply rate $\mathrm{d}E/\mathrm{d} t$, derived from two…

Solar and Stellar Astrophysics · Physics 2018-10-23 René Kiefer , Rudi Komm , Frank Hill , Anne-Marie Broomhall , Markus Roth

Solar gravity (g) modes propagate within the radiative part of the solar interior and are highly sensitive to the physical conditions of the solar core. They would represent the best tool to infer the structure and dynamics of the radiative…

Solar and Stellar Astrophysics · Physics 2015-05-13 S. Mathur , R. A. Garcia , A. Eff-Darwich

In a previous paper we suggested that, for a given p mode, the excitation function is the same as the component of the solar background noise that has an identical surface spherical harmonic projection (over the corresponding range of…

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

We present an analysis of the frequency shift and the even terms of the frequency splitting coefficients carried out using six years of LOWL data, starting in 1994. The temporal variations, and their dependences with the frequency and…

Oscillation mode frequencies of stars are typically treated as static for a given stellar model. However, in reality they can be perturbed by time varying sources such as magnetic fields and flows. We calculate the sensitivities of radial…

Solar and Stellar Astrophysics · Physics 2020-07-01 René Kiefer , Anne-Marie Broomhall

Hydrodynamical, 3D simulations of the outer layers of the Sun and Alpha Cen A are used to obtain constraints on the properties of turbulent convection in such stars. These constraints enable us to compute - on the base of a theoretical…

Astrophysics · Physics 2007-05-23 R. Samadi , M. J. Goupil , F. Baudin , D. Georgobiani , R. Trampedach , R. Stein , A. Nordlund

Normal modes of oscillation of the Sun are useful probes of the solar interior. In this work, we use the even-order splitting coefficients to study the evolution of magnetic fields in the convection zone over solar cycle 23, assuming that…

Solar and Stellar Astrophysics · Physics 2014-11-20 Charles S. Baldner , H. M. Antia , Sarbani Basu , T. P. Larson

The aim of this paper is to investigate whether there are any 11-yr or quasi-biennial solar cycle-related variations in solar rotational splitting frequencies of low-degree solar p modes. Although no 11-yr signals were observed, variations…

Solar and Stellar Astrophysics · Physics 2015-06-04 Anne-Marie Broomhall , David Salabert , William J. Chaplin , Rafael A. Garcia , Yvonne Elsworth , Rachel Howe , Savita Mathur

The observation of g-mode candidates by the SoHO mission opens the possibility of probing the internal structure of the solar radiative zone (RZ) and the solar core more directly than possible via the use of the p-mode helioseismology data.…

Astrophysics · Physics 2008-11-26 T. I. Rashba , V. B. Semikoz , S. Turck-Chieze , J. W. F. Valle

We establish that global solar p-mode frequencies can be measured with sufficient precision on time scales as short as nine days to detect activity-related shifts. Using ten years of GONG data, we report that mode-mass and error-weighted…

Astrophysics · Physics 2009-02-10 S. C. Tripathy , F. Hill , K. Jain , J. W. Leibacher

Although it is well known that the solar acoustic mode frequency increases as the solar activity increases, the mechanism behind it is still unknown. Mode frequencies with 20 < l < 900 obtained by applying spherical harmonic decomposition…

Solar and Stellar Astrophysics · Physics 2015-05-27 M. Cristina Rabello-Soares

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…

Solar and Stellar Astrophysics · Physics 2015-06-12 A. R. G. Santos , M. S. Cunha , J. J. G. Lima

On the one hand, several types of global-scale inertial modes of oscillation have been observed on the Sun. They include the equatorial Rossby modes, critical-latitude modes, and high-latitude modes. On the other hand, the columnar…

Solar and Stellar Astrophysics · Physics 2022-06-08 Yuto Bekki , Robert H. Cameron , Laurent Gizon

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

Solar oscillations consist of a rich spectrum of internal acoustic waves and surface gravity waves, stochastically excited by turbulent convection. They have been monitored almost continuously over the last ten years with high-precision…

Astrophysics · Physics 2010-11-26 L. Gizon