A Coherence Analysis of Fraunhofer Line Radial Velocity Fine Structure and Continuum Brightness Fluctuations near the Center of the Solar Disk.

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Coherence Analysis of Fraunhofer Line Radial Velocity Fine Structure and Continuum Brightness Fluctuations near the Center of the Solar Disk. Edmonds, Frank N., Jr. Abstract Cross correlation analyses between fluctuations in radial velocity V and continuum brightness I have been carried out for four sets of measurements made near the center of the solar disk; those obtained from a McMath-Hulbert spectrogram (w18), those of R. S. Richardson and M. Schwarzschild (Astrophys. J. 111, 351, 1950) (RS), those of H. H. Plaskett (Monthly Notices Roy. Astron. Soc. 114, 251, 1954) (P), and those of R. Servajean (Ann. Astrophys. 24, 1, 1961) (S). These analyses employed a coherence technique which gives the coherence or cross correlation between the Fourier components of the same wavelength for each set of fluctuations, and the phase difference (across the solar disk) between these Fourier components. The analyses also computed power spectra, RMS's and filtered and unfiltered cross correlations. A significant VI coherence with 180~ phase difference was found in the wavelength range 1200-5200 km (on the surface of the sun) for the RS measurements, no VI coherence was found for the w18 measurements, and the S and P measurements gave inconclusive results. These results cannot be explained in terms of differences in the solar atmosphere levels making an appreciable contribution to line formation and to continuum formation. The inconsistent picture presented by the four VI coherence analyses can be explained in terms of a negative VI cross correlation existing for wavelengths ~ 5000 km plus certain differences in instrumental and atmospheric resolution for the four sets of measurements. However, an explanation in terms of a heterogeneous convection pattern at the sun's surface seems more reasonable. Publication: The Astronomical Journal Pub Date: March 1962 DOI: 10.1086/108817 Bibcode: 1962AJ.....67Q.271E full text sources ADS |