Results 91 to 100 of about 5,529 (192)

Meridional Circulation During the Extended Solar Minimum: Another Component of the Torsional Oscillation?

, 2010
We show here a component of the meridional circulation developing at medium-high latitudes (40-50 degrees) before the new solar cycle starts. Like the torsional oscillation of the zonal flows, this extra circulation seems to precede the onset of magnetic
Basu, Beck, Braun, Braun, Chou, Corbard, Gizon, González Hernández, Haber, Howe, Howe, Komm, Miesch, Nesme-Ribes, Zhao   +14 more
core   +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

A Review of Space Helioseismology [PDF]

Symposium - International Astronomical Union, 1997
The helioseismology started in 1960 with the discovery of oscillations of the velocity field on the solar surface by Leighton, 1960. The mechanism producing these oscillations remained unexplained for the next ten years until Ulrich, 1970, and independently Leibacher and Stein, 1971, demonstrated that acoustic waves trapped beneath the solar surface ...
openaire   +1 more source

Editorial: The Future of Asteroseismology

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

Helioseismic Holography of an Artificial Submerged Sound Speed Perturbation and Implications for the Detection of Pre-Emergence Signatures of Active Regions

, 2012
We use a publicly available numerical wave-propagation simulation of Hartlep et al. 2011 to test the ability of helioseismic holography to detect signatures of a compact, fully submerged, 5% sound-speed perturbation placed at a depth of 50 Mm within a ...
A.C. Birch, A.C. Birch, A.D. Crouch, A.G. Kosovichev, C. Lindsey, C. Lindsey, C. Lindsey, C.B. Markwardt, D. Benson, D.C. Braun, D.C. Braun, D.C. Braun, D.C. Braun, D.C. Braun, D.C. Braun, D.C. Braun, D.C. Braun, D.C. Braun, H.-K. Chang, H.-K. Chang, J. Christensen-Dalsgaard, J. Zhao, J.M. Jensen, J.M. Jensen, K.V. Parchevsky, K.V. Parchevsky, R. Cameron, R.H. Cameron, S. Couvidat, S. Ilonidis, S. Ilonidis, S. Ilonidis, S. Zharkov, S.M. Hanasoge, T. Hartlep, T.L. Duvall Jr.   +35 more
core   +1 more source

Differential rotation and radiative equilibrium in the Sun: is the tachocline spreading?

, 2015
It is well known that the combination of barotropic rotation and radiative equilibrium are mutually incompatible in stars. The Sun's internal rotation is far from barotropic, however, which allows at least the theoretical possibility that the Sun's ...
Balbus, Steven, Caleo, Andrea, Potter, William   +2 more
core   +1 more source

A Linear Model for Inertial Modes in a Differentially Rotating Sun

The Astrophysical Journal
Inertial wave modes in the Sun are of interest owing to their potential to reveal new insight into the solar interior. These predominantly retrograde-propagating modes in the solar subsurface appear to deviate from the thin-shell Rossby–Haurwitz model at
Jishnu Bhattacharya, Chris S. Hanson, Shravan M. Hanasoge, Katepalli R. Sreenivasan   +3 more
doaj   +1 more source

Helioseismology and the solar age [PDF]

, 1998
The problem of measuring the solar age by means of helioseismology hasbeen recently revisited by Guenther & Demarque (1997) and by Weiss & Schlattl (1998). Different best values for $t_{\rm seis}$ and different assessment of the uncertainty resulted from
Dziembowski, W. A., Fiorentini, G., Ricci, B., Sienkiewicz, R.   +3 more
core   +1 more source

Helioseismology and Asteroseismology: Looking for Gravitational Waves in acoustic oscillations

, 2014
Current helioseismology observations allow the determination of the frequencies and surface velocity amplitudes of solar acoustic modes with exceptionally high precision. In some cases, the frequency accuracy is better than one part in a million. We show
Lopes, Ilídio, Silk, Joseph
core   +2 more sources

Predicting Solar Magnetic Activity from Sph and Seismic Parameters Using Random Forest Regression

The Astrophysical Journal
We investigate the potential of using the photometric magnetic proxy S _ph and seismic parameters, such as the frequency of maximum power ( ${\nu }_{{\rm{\max }}}$ ) and the large frequency separation (Δ ν ), derived from Solar and Heliospheric ...
Ki-Beom Kim, Heon-Young Chang
doaj   +1 more source