Results 81 to 90 of about 1,537 (202)

Understanding the Travel-time Asymmetry of Acoustic Waves in Sunspots with Time–Distance Helioseismology

The Astrophysical Journal
Mapping the subsurface structure and flow field of sunspots has been a challenging task for helioseismology. In this work, we investigate the propagation of acoustic waves in a sunspot in NOAA active region 11312 using time–distance helioseismology ...
Haiyu Li, Tobías Felipe, Elena Khomenko, Hui Tian, S. P. Rajaguru, Yuhang Gao   +5 more
doaj   +1 more source

Time-dependence of Subsurface Solar Convection Using the Time–Distance Deep-focus Method

The Astrophysical Journal
We reexamine the deep-focus methodology of time–distance helioseismology previously used to estimate the power spectrum of the solar convection at a depth of about 30 Mm, which was found to be significantly weaker than predicted by theory and simulations.
John T. Stefan, Alexander G. Kosovichev, Gustavo Guerrero, Andrey M. Stejko   +3 more
doaj   +1 more source

Time-Distance Helioseismology: Noise Estimation

, 2004
As in global helioseismology, the dominant source of noise in time-distance helioseismology measurements is realization noise due to the stochastic nature of the excitation mechanism of solar oscillations.
Gizon, Laurent, A. C. Birch, L. Gizon, Birch, A. C.   +3 more
core   +1 more source

Helioseismic Signature of Parker Fragmentation of Magnetic Flux beneath Sunspot Photospheres

The Astrophysical Journal Letters
Standard local helioseismic diagnostics of large sunspots show the signature of anomalously strong compact scatterers of p -modes within about 1 Mm beneath their photospheres.
Elena G. Broock, Angel Mart Cifuentes, Alina-Catalina Donea, Charles Lindsey   +3 more
doaj   +1 more source

Editorial: The Future of Asteroseismology

Frontiers in Astronomy and Space Sciences, 2021
Joyce Ann Guzik, Markus Roth
doaj   +1 more source

A Core-sensitive Mixed f/g-mode of the Sun Predicted by Wave Topology and Hydrodynamical Simulation

The Astrophysical Journal Letters
Helioseismology has revolutionized our understanding of the Sun by analyzing its global oscillation modes. However, the solar core remains elusive, limiting a full understanding of its evolution.
Arthur Le Saux, Armand Leclerc, Guillaume Laibe, Pierre Delplace, Antoine Venaille   +4 more
doaj   +1 more source

Stray Light Correction for the Helioseismic and Magnetic Imager

The Astrophysical Journal Supplement Series
We report a point-spread function (PSF) and deconvolution procedure to remove stray light from the Helioseismic and Magnetic Imager (HMI) data. Prelaunch calibration observations, postlaunch Venus transit, and lunar transit data were used to develop the ...
A. A. Norton, T. L. Duvall Jr., J. Schou, R. S. Bogart, Junwei Zhao, M. C. Rabello-Soares, P. J. Levens, J. T. Hoeksema, C. S. Baldner   +8 more
doaj   +1 more source

Dynamics of Large-Scale Solar Flows. [PDF]

Space Sci Rev, 2023
Hotta H, Bekki Y, Gizon L, Noraz Q, Rast M.   +4 more
europepmc   +1 more source

New Solar Metallicity Measurements

Atoms, 2019
In the past years, a systematic downward revision of the metallicity of the Sun has led to the “solar modeling problem„, namely the disagreement between predictions of standard solar models and inferences from helioseismology.
Sunny Vagnozzi
doaj   +1 more source

Neutrino Helioseismology

, 1992
The observed deficit of $\rm ^8B$ solar neutrinos may call for an improved standard model of the sun or an expanded standard model of particle physics ({\it e.g.,} with neutrino masses and mixing). In the former case, contemporary fluid motions and thermal fluctuations in the sun's core may modify nuclear reaction rates and restore agreement.
De Rújula, A., Glashow, S. L.
openaire   +2 more sources