Observation of Additional Low-Degree Five-Minute Modes of Solar Oscillation

By measuring the difference between the shifts in the Fe 5124 spectrum line from light integrated from a central circular portion of the solar disk and from an annular portion exterior to it, we have been able to detect high-order solar oscillations with degrees l = 3, 4 and 5. The frequencies of th...

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Bibliographic Details
Main Authors: Scherrer,Philip H, Wilcox,John M, Christensen-Dalsgaard,Jorgen, Gough,Douglas
Other Authors: STANFORD UNIV CA INST FOR PLASMA RESEARCH
Format: Text
Language:English
Published: 1982
Subjects:
Astrophysics
*Sun
*Oscillation
*Spectrometry
Sunlight
Line spectra
Doppler effect
South Pole
South pole
Online Access:http://www.dtic.mil/docs/citations/ADA118805
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA118805
Description
Summary:By measuring the difference between the shifts in the Fe 5124 spectrum line from light integrated from a central circular portion of the solar disk and from an annular portion exterior to it, we have been able to detect high-order solar oscillations with degrees l = 3, 4 and 5. The frequencies of the octupole modes agree well with the values obtained from whole-disk measurements at the South Pole. A least-squares fit of the observed frequencies to values interpolated between and extrapolated from the predictions of a sequence of solar models with different chemical compositions selects a model with a helium abundance somewhat greater than 25 per cent by mass.

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