The [Fe II] and [Fe III] emission of seven galactic H II regions is studied with the aim of comparing their gaseous Fe abundance. The [Fe II] line intensity ratios are found to behave in a manner that suggests fluorescence effects. In addition, the uncertainty in the physical conditions and the ionization stratification of the layers where [Fe II]

Planets forming around close binary systems should form in the binary orbital plane (varying precession periods of protoplanetary material should provide strong collisional damping; Schneider and Doyle 1995). Planets around eclipsing binaries may then be expected to have formed in the binary orbital plane and thus to be detected by their transits

Beryllium is a key element for constraining mixing processes taking place in the interiors of late-type dwarfs, and this paper investigates the use of neutral beryllium lines to obtain reliable abundances. The best candidate, among other Bei features, is the ^9^Bei λ2348.609A resonance line. Its spectral location, well below the Earth's UV

We present Keck Observatory 10 m telescope spectra of the two Pleiades brown dwarfs, Teide 1 and Calar 3, showing a clear detection of the Li 670.8 nm resonance line. In Teide 1, we have also obtained evidence for the presence of the subordinate line at 812.6 nm. A high Li abundance [log N(Li) >= 2.5], consistent with little if any depletion, is

We report intermediate resolution spectroscopy (50 km/s) of the magnetic Cataclysmic Variable AE Aqr performed as part of the World Astronomy Days (WAD) campaign. Our analysis of the absorption features supports a K4 classification for the companion star, which contributes more than 95% of the total flux in the range 600-700 nm. We find that the

In this timely volume, the editors present eight specially-written chapters by experts renowned for their teaching skills. The chapters show how astronomers can deduce the internal composition (density, helium abundance, etc.) and dynamical structure (rotation, sub-surface velocity fields, etc.) of the Sun through helioseismology, and how