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  • 1
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 293 (1981), S. 443-445 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Each phenomenon discovered by Doppler shift measurements has yielded unexpected information in view of the then current theoretical models of the Sun. The long period oscillation (160 m), also found3 using a different technique, is more than double the gravest radial mode predicted by linear ...
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 282 (1979), S. 591-594 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Doppler shift measurements of integral solar light show several discrete lines of amplitude 0.1-0.3 m s"1 within the main peak of the power spectrum of the 5-min oscillation. These lines are found to have, on average, a uniform spacing of 67.8 ??. If the lines are interpreted as being due to low / ...
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 259 (1976), S. 92-95 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The Fraunhofer absorption lines for potassium and sodium on the Sun are compared with the corresponding lines in the laboratory using a resonant optical scattering method. The observed shifts between the Sun and laboratory lines may be interpreted in terms of the gravitational redshift (GRS), ...
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 299 (1982), S. 704-706 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1 A diagrammatic representation of the potassium 769.9-nmFraunhofer absorption line illustrating the mean relative sitionof the laboratory Zeeman components at two different epochs. The availability of the present long data stretches makes it possible to search for longer periods, several ...
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 333 (1988), S. 646-649 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Extensive data obtained at the Observatorio del Teide (Izafia, Tenerife) from 1977 to 1985 are analysed to determine the lifetimes and frequencies of the /0 and /t p-modes. The import-ance of the lifetime of the mode in determining the frequency is considered. From an analysis of the phase and ...
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An analysis of 28 contiguous days of whole disk observations of the solar surface by means of optical resonant scattering in the K 769.9 nm line, taken at the Teide Observatory at Izana during July–August 1980, have thus far yielded two significant facts. Firstly when the results of an iterative sine-wave fitting procedure are considered in the period range 2–3 h, although the expected daily harmonics corresponding to 1/8, 1/10, 1/11, and 1/12 of a day are clearly seen the l/9th contribution is significantly absent. It is suggested that this results from an interference between a signal of 160 min (1/9th of a day) with the daily harmonic. It is further pointed out that the observatories at which the 160 min oscillation has been seen, Crimea, Pic du Midi, and Stanford are all separated by integral numbers of 160 min, and thus the phase of the 160 min oscillation relative to the daily observation window is constant. However, the Teide Observatory is situated at a half integral number of 160 min periods relative to the others. Thus when constructive interference exist at the first three sites destructive interference will exist at the latter. It is thus concluded that the non-existence of a peak corresponding to the 1/9th harmonic of a day in the sine-wave fit data is strong indirect evidence for the existence of the 160 min signal. An analysis of those same data in the 5 min region has revealed the now well established pattern of discrete frequencies and with the increased resolution obtainable from 28 contiguous days of data, clearly showed the existence of splitting by rotational effects. In all 33 discrete lines were considered in the frequency range 2.4–3.85 mHz, which could be divided up into 3 groups, each of 11 lines, corresponding to the l = 0, l = 1, and l= 2 modes. This definitive classification was possible as the lines are split into (2l + 1) components yielding easily identifiable singlets, triplets and quintuplets. This first observation of the rotational splitting of solar oscillations gave the further information that the splitting of 0.75 ± 0.10 μHz indicated that the solar interior is rotating more rapidly than the observable surface (uniform rotation would yield a splitting of 0.4 μHz). A comparison of the widths of the individual peaks, with the intrinsic resolution of the data string (∼ 1/T where T = length of the data string), showed that these were consistent with a high Q value oscillation, a fact which is further confirmed by the very existence of singlets triplets and quintuplets in the data. The exact value of the speed of internal rotation of the Sun can only be deduced from these data by a model dependent calculation. The simplest of these would suggest that if the core were almost equal to the solar diameter then it is rotating twice as fast as the surface, whereas if the core were only 15% of the solar diameter, it would be rotating at 9 times the surface rate.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Solar physics 74 (1981), S. 503-508 
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A precise two-dimensional positioning device has been developed for use in conjunction with a resonant scattering spectrometer to study the spatial distribution of solar velocity fields. The principle of operation and constructional details are discussed and the experimental performance is evaluated. As an illustration of its use preliminary data obtained from a meridional scan are presented.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Since 1981 we have been operating the Birmingham Solar-Oscillations Network (BiSON), a global network of resonant-scattering spectrometers, observing the low-l solar p modes. Here we discuss historical developments, culminating in the establishment of a 6-station network in 1992 September, and the subsequent performance of that network. The data record of each station from 1992 to 1994 has been analysed in terms of weather and equipment breakdowns. Our early experience suggests that the best long-term coverage possible with a 6-station network is limited in practice to about 80%, which falls short of previous predictions.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Solar physics 74 (1981), S. 51-57 
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The discrete structure in the 5 min velocity oscillations of the solar surface has been confirmed by a re-analysis of data obtained between 1976 and 1979, and in addition a preliminary analysis of 1980 data show excellent consistency of the determined frequencies over the five year period. It is further shown that atmospheric transparency, as measured by the power in the solar intensity fluctuations, shows no correlation with the measured amplitude of the velocity fluctuations, over 2 orders of magnitude.
    Type of Medium: Electronic Resource
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