An observational investigation of long period oscillations in the apparent solar diameter. Doctoral thesis

Technical Report · Sat Jan 01 04:00:00 EST 1977

OSTI ID:7256333

Brown, T M

Observations of the apparent solar diameter were undertaken to determine whether long-period oscillations might be present. The observations discussed consist of 11 time series of the solar diameter, averaging 7 h in length. Power spectrum analyses of these time series reveal oscillations throughout the 3 to 7 min period range, with typical amplitudes of 2 X 10-/sup 6/ of the solar diameter. A careful consideration of random and systematic errors and a statistical analysis of the power spectra show that the oscillations are almost certainly a solar phenomenon, and not an observational artifact. It is suggested that the oscillations are normal mode vibrations of the entire sun. A simple theory is presented describing waves in an atmosphere with a constant temperature gradient and Newton's law cooling, and used to demonstrate that the normal modes interpretation is consistent with available observations of temperature and radial velocity, as well as with those of the apparent diameter. The observed oscillation periods are in good agreement with predictions based on current models of the sun. Since these periods may yield direct information about the sun's interior, the observability of the oscillations may be of great importance for the study of solar structure.

• Research Organization: National Center for Atmospheric Research, Boulder, CO (USA)
• OSTI ID: 7256333
• Report Number(s): PB-265726; NCAR-CT-42
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
DIMENSIONS
ERRORS
MECHANICAL VIBRATIONS
OSCILLATIONS
SIZE
SOLAR ATMOSPHERE
STARS
SUN
TIME DEPENDENCE
VARIATIONS