The nonlinear development of the kink instability of a magnetic flux tube initially lying in mechanical equilibrium in the deep convection zone is presented. The unstable evolution is started by a small-amplitude sinusoidal perturbation of the shape of the flux tube in a vertical plane. As a result of the development of the instability, the lower

Single-epoch multifrequency data for the BL Lac objects OI 90.4 and 3C 66A, spanning radio through ultraviolet wavelengths, are presented, as well as other measurements relevant to intensity and spectral-shape variability. Both BL Lac objects exhibit spectral curvature in the infrared-to-ultraviolet region, a properity that is inferred to be usual

IUE spectra of Mg II h and k in late type dwarfs and giants were used to detect and measure absorption components due to the LISM. This technique gives a method of probing the awkward range from d = 3 pc to d = 80 pc from the Sun. In spite of interpretational uncertainties the HI component of the LISM can be plotted well enough to confirm it as a

Detection of narrow (δλ 0.5 Å) absorption features in C IV at λλ1548 and 1550 have been made in the spectra of 4 late B dwarfs within 200 pc of the sun; the Si IV doublet at λλ1393 and 1403 shows up in two of them. The authors argue that it is difficult to account for the strengths, widths, shapes, and C IV/Si IV ratios in terms consistent with a

The solar cycle was studied by considering only the large active regions (AR), with small region data being ignored. Results show that at birth almost all the large AR display the correct inclination (p-part at lower latitude) while the small AR show random behavior. The maximum latitude attained by the large AR is lower by 10 deg than that of the

It is reported that 8-13-micron spectra have been obtained at several positions across the extended emission region of M82. No major differences among the spectra are found. In addition, a strong similarity is found between these spectra and the infrared spectrum of the Orion ionization front. The data are interpreted using a model for M82 in which