The center-limb behavior of solar molecular lines

The center-limb behavior of C₂, CH, CN, CO, and MgH lines have been analyzed using five photospheric models. A three-stream model developed by G. Elste gave the most satisfactory results, providing evidence for the existence of inhomogeneities in the photospheric layers - 2.5 log 5000 -0.5.     

A modified first-motion approximation for the synthesis of body-wave seismograms

Summary. Modified first-motion approximations have been developed for the generation of synthetic body-wave seismograms using the Cagniard-de Hoop method. Comparisons are presented between classical first motion, modified first motion and full Cagniard treatments for problems involving a homogeneous sphere and a triplication in a realistic earth model. Results of these comparisons show that the modified first-motion approximations may be used for a wide variety of geophysically interesting problems with little loss of accuracy compared to the full Cagniard method.     

Solar XUV limb brightening observations

Limb brightening of XUV lines of the ions Ciii Niii, Niv, Oiii, Oiv, Ov and Siiv is compared with that predicted by a modified version of a coronal model developed by Dupree and Goldberg. Systematic differences between the predicted and observed limb brightening are found. These differences can be eliminated by introducing into the model the effects of spicules that extend up into the chromospheric-coronal transition region. The spicules are assumed to be opaque to radiation between 500 and 900 Å because of absorption in the hydrogen Lyman continuum.