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Asymmetries of solar oscillation line profilesAsymmetries of the power spectral line profiles of solar global p-modes are detected in full-disk intensity observations of the Ca II K Fraunhofer line. The asymmetry is a strong function of temporal frequency being strongest at the lowest frequencies observed and vanishing near the peak of the power distribution. The variation with spherical harmonic degree is small. The asymmetry is interpreted in terms of a model in which the solar oscillation cavity is compared to a Fabry-Perot interferometer with the source slightly outside the cavity. A phase difference between an outward direct wave and a corresponding inward wave that passes through the cavity gives rise to the asymmetry. The asymmetry is different in velocity and intensity observations. Neglecting the asymmetry when modeling the power spectrum can lead to systematic errors in the measurement of mode frequencies of as much as 10 exp -4 of the mode frequency. The present observations and interpretation locate the source of the oscillations to be approximately 60 km beneath the photosphere, the shallowest position suggested to date.
Document ID
19930057118
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Duvall, T. L., Jr.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Jefferies, S. M.
(Bartol Research Inst. Newark, DE, United States)
Harvey, J. W.
(National Solar Observatory Tucson, AZ, United States)
Osaki, Y.
(Tokyo Univ. Japan)
Pomerantz, M. A.
(Bartol Research Inst. Newark, DE, United States)
Date Acquired
August 16, 2013
Publication Date
June 20, 1993
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 410
Issue: 2
ISSN: 0004-637X
Subject Category
Solar Physics
Accession Number
93A41115
Funding Number(s)
CONTRACT_GRANT: NSF DPP-87-15791
CONTRACT_GRANT: NSF DPP-89-17626
Distribution Limits
Public
Copyright
Other

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