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Related papers: GONG p-mode frequency changes with solar activity

200 papers

Context. The Sun and solar-like stars undergo activity cycles for which the underlying mechanisms are not well understood. The oscillations of the Sun are known to vary with its activity cycle and these changes provide diagnostics on the…

Solar and Stellar Astrophysics · Physics 2017-02-08 René Kiefer , Ariane Schad , Guy Davies , Markus Roth

We used long high-quality unresolved (Sun-as-a-star observations) data collected by GOLF and VIRGO instruments on board the ESA/NASA SOHO satellite to investigate the amplitude variation with solar cycle 23 in the high-frequency band (5.7 <…

Solar and Stellar Astrophysics · Physics 2015-05-13 R. Simoniello , W. Finsterle , R. A. Garcia , D. Salabert , A. Jimenez

This paper examines long-term temporal and spatial fluctuations in the solar rotation (more than four solar cycles) by investigating radio emission escapes from various layers of the solar atmosphere during the years 1967-2010. The flux…

Solar and Stellar Astrophysics · Physics 2021-07-06 Vivek Kumar Singh , Satish Chandra , Sanish Thomas , Som Kumar Sharma , Hari Om Vats

In helioseismic studies, an observational parameter of primary concern is the P-angle, the angle along which lies the solar axis of rotation for a given image. For the six observing sites employed by The Global Oscillation Network Group…

Solar and Stellar Astrophysics · Physics 2023-04-17 Anna L. H. Hughes , Irene Gonzalez-Hernandez , Sean G. McManus , Kiran Jain , Sushanta C. Tripathy

Solar activity and solar wind parameters decreased significantly in solar cycles (SCs) 23-24. In this paper, we analyze solar wind measurements at the rising phase of SC 25 and compare them with similar data from the previous cycles. For…

Properties of stars undergoing pulsation such as the well known root-mean-density scaling relation can be useful when trying to match the observed properties of a particular star. It is often assumed that this relation is valid for p mode…

Solar and Stellar Astrophysics · Physics 2016-04-27 Diego Castañeda , Robert G. Deupree

Context. Solar activity cycles vary in amplitude and duration. The variations can be at least partly explained by fluctuations in dynamo parameters. Aims. We want to restrict uncertainty in fluctuating dynamo parameters and find out which…

Solar and Stellar Astrophysics · Physics 2018-07-18 L. L. Kitchatinov , A. V. Mordvinov , A. A. Nepomnyashchikh

The minimum of solar cycle 24 is significantly different from most other minima in terms of its duration as well as its abnormally low levels of activity. Using available helioseismic data that cover epochs from the minimum of cycle 23 to…

Solar and Stellar Astrophysics · Physics 2015-05-19 H. M. Antia , Sarbani Basu

We use 9.5-yr of BiSON Sun-as-a-star data to search for dependence of solar-cycle parameter changes on the angular degree, l, of the data. The nature of the Sun-as-a-star observations is such that for changes measured at fixed frequency, or…

Astrophysics · Physics 2009-11-11 D. Salabert , W. J. Chaplin , Y. Elsworth , R. New , G. A Verner

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

Herein we adopt a multi-scale dynamical spectral analysis technique to compare and study the dynamical evolution of the harmonic components of the overlapping ACRIMSAT/ACRIM3, SOHO/VIRGO and SORCE/TIM total solar irradiance (TSI) records…

General Physics · Physics 2013-11-28 Nicola Scafetta , Richard C. Willson

Context. The relation between solar surface rotation and sunspot activity still remains open. Sunspot activity has dramatically reduced in solar cycle 24 and several solar activity indices and flux measurements experienced unprecedentedly…

Solar and Stellar Astrophysics · Physics 2015-02-18 L. Zhang , K. Mursula , I. Usoskin

Using continuous observations for 22 years from ground-based network GONG and space-borne instruments MDI onboard {\it SoHO} and HMI onboard {\it SDO}, we report both global and local properties of the convection zone and their variations…

Solar and Stellar Astrophysics · Physics 2019-01-30 Kiran Jain , Sushanta Tripathy , Rudolf Komm , Frank Hill , Rosaria Simoniello

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 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

The characteristic of the solar acoustic spectrum is such that mode lifetimes get shorter and spatial leaks get closer in frequency as the degree of a mode increases for a given order. A direct consequence of this property is that…

Astrophysics · Physics 2009-11-07 S. G. Korzennik , M. C. Rabello-Soares , J. Schou

Context: Solar sectoral Rossby waves have only recently been unambiguously identified in Helioseimsic and Magnetic Imager (HMI) and Michelson Doppler Imager (MDI) maps of flows near the solar surface. So far this has not been done with the…

Solar and Stellar Astrophysics · Physics 2020-03-18 Chris S. Hanson , Laurent Gizon , Zhi-Chao Liang

In the present work we show robust indications of the existence of g modes in the Sun using 10 years of GOLF data. The present analysis is based on the exploitation of the collective properties of the predicted low-frequency (25 to 140…

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…

Astrophysics · Physics 2007-05-23 M. Cunha , M. Bruggen , D. O. Gough

Using the recently obtained GONG frequencies, we investigate the properties of the solar interior by constructing solar models with various input physics like opacities, equation of state, nuclear reaction rates etc. The differential…

Astrophysics · Physics 2007-05-23 S. C. Tripathy , H. M. Antia , F. Hill , A. Ambastha