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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

Asteroseismic modelling is crucial for upcoming missions like PLATO, CubeSpec, and Roman. Despite significant progress, discrepancies between observations and theoretical predictions introduce biases in stellar characterisation at the…

Solar inter-network magnetic field is the weakest component of solar magnetism, but contributes most of the solar surface magnetic flux. The study on its origin has been constrained by the inadequate tempo-spatial resolution and sensitivity…

Solar and Stellar Astrophysics · Physics 2015-05-26 Chunlan Jin , Jingxiu Wang

Context. Large-amplitude inversions of the solar wind's interplanetary magnetic field have long been documented; however, observations from the Parker Solar Probe (PSP) mission have renewed interest in this phenomenon as such features,…

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…

Astrophysics · Physics 2009-10-30 Sarbani Basu

Waves are thought to play a significant role in the heating of the solar atmosphere and the acceleration of the wind. Among the many types of waves observed in the Sun, the so-called p-modes with a 3 mHz frequency peak dominate the lower…

We argue that a variety of solar data suggest that the activity-cycle timescale variability of the total irradiance, is produced by structural adjustments of the solar interior. Assuming these adjustments are induced by variations of…

Astrophysics · Physics 2009-10-31 L. H. Li , S. Sofia

We present results on the structure of the near-surface layers of the Sun obtained by inverting frequencies of high-degree solar modes from "ring diagrams". We have results for eight epochs between June 1996 and October 2003. The…

Astrophysics · Physics 2008-11-26 Sarbani Basu , H. M. Antia , Richard S. Bogart

We test the relation between relative f-mode frequency variation and Lagrangian perturbation in the solar radius obtained by Dziembowski and Goode (2004) using several pairs of solar models and show that it doesn't hold true for any of the…

Astrophysics · Physics 2009-11-13 Piyali Chatterjee , H M. Antia

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…

Astrophysics · Physics 2016-08-16 S. J. Jiménez-Reyes , T. Corbard , P. L. Pallé , T. Roca Cortés , S. Tomczyk

The principal aim of observational helioseismology is to determine mode parameters of the solar oscillations as accurately as possible. Yet estimates of the mode parameters are subject to many sources of noise, including inevitable gaps in…

Astrophysics · Physics 2009-11-07 Heon-Young Chang

Magnetic activity effects are typically neglected in asteroseismic modelling of solar-type stars, presuming that these effects can be accounted for in the parametrisation of the surface effects. It was however demonstrated that magnetic…

Solar and Stellar Astrophysics · Physics 2025-07-16 Jérôme Bétrisey , Anne-Marie Broomhall , Sylvain N. Breton , Rafael A. García , Henry Davenport , Oleg Kochukhov

The Sun's magnetic dynamo cycle features a distinct pattern: a propagating region of sunspot emergence appears around 30 degrees latitude and vanishes near the equator every 11 years. Moreover, longitudinal flows called "torsional…

Among many other measurable quantities the summer of 2009 saw a considerable low in the radiative output of the Sun that was temporally coincident with the largest cosmic ray flux ever measured at 1AU. A hemispheric asymmetry in magnetic…

Several works have reported changes of the Sun's subsurface stratification inferred from f-mode or p-mode observations. Recently a non-homologous variation of the subsurface layers with depth and time has been deduced from f-modes. Progress…

Astrophysics · Physics 2011-02-11 Sandrine Lefebvre , Phu Anh Phi Nghiem , Sylvaine Turck-Chieze

We discuss properties of large amplitude magnetic field fluctuations during fast Alfvenic solar wind streams, focussing on the statistics of the rotation angle between consecutive magnetic field vector measurements for different scales in…

Space Physics · Physics 2019-10-17 L. Matteini , D. Stansby , T. S. Horbury , C. H. K. Chen

We present a comprehensive statistical study of the radial evolution of solar wind turbulence near Mercury's orbit using long-term magnetic field measurements from the MESSENGER mission. Owing to Mercury's highly elliptical orbit and the…

We measure the mean frequencies of acoustic waves propagating toward and away from a sunspot employing a spot-centered Fourier-Hankel decomposition of p-mode amplitudes as measured from a set of observations made at the South Pole in 1991.…

Astrophysics · Physics 2007-05-23 D. C. Braun , Y. Fan , C. Lindsey , S. M. Jefferies

We show that chirping gravitational waves in the LIGO frequency band $f=1 - 5000$ Hz can be gravitationally diffracted by the Sun, due to the coincidence of its Fresnel length $r_F \propto \sqrt{1\, {\rm AU}/f}$ and the solar radius…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-26 Sunghoon Jung , Sungjung Kim

In addition to the well-known 11-year solar cycle, the Sun's magnetic activity also shows significant variation on shorter time scales, e.g. between one and two years. We observe a quasi-biennial (2-year) signal in the solar p-mode…

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