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

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 ~> 41 days. Large-scale differential refraction effects have been reduced by a factor of l0 S 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.

Properties of r-modes in the Sun

“…Some recent papers are Ulrich and Rhodes (1983), Grec et al (1983), Bos and Hill (1983), Woodard and Hudson (1983), Wolff (1983), and Delache and Sherrer (1983). But there is another type of global mode, the r-mode, which is rarely mentioned in a solar context.…”

Stellar 5 min Oscillations

“…For solar oscillations such analyses were carried out by Deubner (1981), Claverie etal. (1981, and Bos and Hill (1983). Alternatively a continuous record could be obtained by combining data from several different obseruse, available at https://www.cambridge.org/core/terms.…”

On the origin of oscillations in a solar diameter observed through the Earth's atmosphere: A terrestrial atmospheric or a solar phenomenon

“…These properties are also listed in Table I and have been reported in a number of papers spread over the last six years. These references and the salient points from these works will be brought together in the following paragraphs, culminating with the most recent results of Bos and Hill (1983). (Bos and Hill, 1983).…”

“…These references and the salient points from these works will be brought together in the following paragraphs, culminating with the most recent results of Bos and Hill (1983). (Bos and Hill, 1983). Each of these sets of observations of solar oscillations has, upon analysis, exhibited properties which fall into two or more of the five categories which are listed in "Fable I.…”

“…For the highest frequency resolution that has been reported to date in the observations, the whole disk velocity amplitudes are of the order of 10 cm per sec (Claverie et al, 1981), while the amplitudes of the diameter variations are of the order of a few milli arc sec (Bos and Hill, 1983). When the small size of these amplitudes is put into perspective, it is reasonable to expect that the presence of the Earth's atmosphere may pose problems.…”