Detection of Individual Normal Modes of Oscillation of the Sun in the Period Range from 2 Hr to 10 Min in Solar Diameter Studies

Abstract

Abstract. New observations of solar oscillations are reported. Power density spectra derived from these observations reveal narrow-band oscillations that are spatially global, have spatial symmetry properties that are either symmetric or antisymmetric for reflection about the center of the solar disk and also about the solar equator, and have coherence times j>41 days. Large-scale differential refraction effects have been reduced by a factor of 10 5 over that found in previous solar diameter studies by the design of the experiment; thus, these effects are eliminated as a possible source of the oscillations. A discussion is presented of this reduction as well as other features of the observing and analysis program. It is concluded that the probability is very high that individual normal modes of oscillation of the Sun have been detected in the period range from 2 hr to 10 min.