We present preliminary results on the analysis of very deep echelle UVES (8m VLT) spectra of the Galactic H II region S311 (NGC 2467) located outside the Solar circle. The data cover from 3100 to 10450 Å with a resolution R ~ 8800. We have detected and measured more than 300 emission lines, some of them are faint recombination lines of heavy

Not Available

At present, the precision of deep ultraviolet photometry is somewhat limited by the dearth of faint ultraviolet standard stars. In an effort to improve this situation, we present a uniform catalog of 11 new faint (u ~ 17) ultraviolet standard stars. High-precision photometry of these stars has been taken from the Sloan Digital Sky Survey and Galaxy

Some observations suggest that quiescent solar prominences can be considered as composed by small-scale loops, or fibrils, which are stacked one after another in both the vertical and horizontal directions. In a previous work we studied, in Cartensian geometry, the propagation of fast MHD waves in a two-dimensional magnetostatic model representing

High-resolution observations suggest that quiescent solar prominences are made of small-scale fibrils stacked one after another in both the vertical and horizontal directions. These fibrils are interpreted as the cool, highermost part of much larger coronal loops which are rooted in the solar photosphere. On the other hand, there is some evidence

The photospheric temperature minimum in the Sun and solar-like stars is very weakly ionized, with an ionization fraction f as low as 10‑4. In galactic star-forming regions, f can be 10‑10 or lower. Under these circumstances, the Hall current can couple low-frequency Alfvén and magnetoacoustic waves via the dimensionless Hall parameter ε =ω /{{{Ω }}