Radial velocity discriminated coronal photometric measurements at the July 11, 1991 total eclipse

The results from a set of 12 solar corona radial velocity measurements in the 400-440 nm spectral band during the total solar eclipse of July 11, 1991 are reported. The measurements show that the orbital motion of the F-corona material near the sun in the ecliptic plane is consistent with Keplerian motion and predominantly, but not exclusively, prograde, as is usually assumed. This work demonstrates a method of using the measured radial velocities to sort out the relative amounts of K-corona, near-earth F-corona, near-solar F-corona, and scattered light in each measurement for each observation point W and E of the sun between 2.5Ro(solar radii) and 5Ro along the celestial equator and at three points north of the sun. The near-solar F-corona component is quite weak, contributing only 7-14% of the total signal in each case. The stronger diffraction component from near-earth F-corona is estimated to have been produced by particles with radii of about 11μ. In contrast, the scattered light component appears as strong zero-velocity features dominating all the measurements. The measurements W and E of the sun and near the ecliptic plane also show evidence of a red-shift velocity of at least 330 km s−1, suggestive of a high-speed dust outflow from the sun.