No abstract available

[en] The work of various groups, which have been investigating the possibility of measuring the periodicities of solar oscillations in an attempt to test theoretical models of the sun, is reported. In particular the observation of small velocity oscillations of the surface layers of the sun that permits the measurement of the sound waves (or phonons) in the solar atmosphere, is discussed. Oscillations with periods of 2.65 h, 58 and 40 min and amplitudes of 2.7, 0.8 and 0.7 ms^-1 respectively are reported. Support for a periodicity at about 2.65 h from a number of other groups using other measuring techniques are considered. It is felt that the most probable interpretation of the observed solar oscillations is that the sun is a resonator which is ringing. (UK)

No abstract available

[en] The possible correlation between the size of observed rotational splitting of the non-radial p modes of 1 = 1 and 1 = 2 (with n approximately 20) of the 5-min global oscillation of the Sun with the enigmatic 12.2-day variation in the measurement of solar oblateness discovered previously, is examined. An interpretation is given of the observed near equality of the amplitudes of the m-components of the 1 = 1 and 1 = 2 rotationally split modes which leads to the first empirical evidence that an asymmetric magnetic rotator with megagauss magnetic fields exists in the interior of the Sun and suggests that the magnetic energy of young stars is a sizeable fraction of their gravitational energy. (U.K.)

[en] Observation of global oscillations of the Sun constitutes a primitive seismology of the solar interior. The frequencies, if correctly identified with definite normal modes of vibration. Provide a measure of the average velocity of sound in the interior and thereby of its composition and temperature. Fine structure in the frequencies of nonradial modes may provide information on their character (multiplicity) and on the rotation of the solar interior. Study of the amplitudes and phase fluctuations of the vibrations may clarify the excitation and damping of the vibrations. After a brief historical review emphasizing global velocity spectroscopy an account is given of the present status of the observations of global oscillations in the range of periods of 3 to 160 min. Finally the future capabilities of the observational techniques and their resultant potential is discussed. (orig.)

[en] The Star Procyon (α CMi) was observed for 2 weeks using the Birmingham double magneto-optical filter spectrometer on the 1.9 m reflector of the South African Astronomical Observatory in 1988 January. Our analysis of these velocity data shows that the noise level in the power spectrum of the combined nightly runs is approximately 12 m² s^-2. These data were searched for the presence of small scale oscillations, but none were obviously present. On one night the surface integrated magnetic field of Procyon was measured using a rotating quarter wave plate to select alternatively opposite senses of circularly polarised light

[en] An attempt has been made to detect short-period solar luminosity fluctuations in the vicinity of 5 min, analogous to the observed velocity oscillation. Using silicon photodiodes to monitor integral sunlight, an upper limit for the amplitude of the intensity fluctuations of 3 x 10^-5 rms was found. (orig.)

[en] Measurements of the even-even isotope shifts in seven Sm spectral lines made using tunable dye laser heterodyne spectroscopy are presented. Anomalies in the isotope shifts in the level at 19 192 cm^-1 in the Sm I spectrum reported previously have been confirmed to within experimental uncertainty by data from the line at 564.75 nm which couples to that level. Results from the line at 565.28 nm show equal and opposite deviations, from straight lines fitted through King plots, to the anomalies produced by the data from the 19 192 cm^-1 level. (author)

No abstract available

[en] The Fraunhofer absorption lines for K and Na 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, motion of the laboratory relative to the Sun and oscillatory terms which may be related to oscillations of the Sun. (author)