We present kinematical evidence that the irregular galaxy located 26'' northwest of IZw18 -the most metal-poor blue-compact-dwarf (BCD) galaxy known- is a dynamically associated companion system. Longslit CCD spectra were obtained in 1996 February using the 4.2m WHT+ISIS at La Palma, with the slit placed across the NW HII region of IZw18 and

This paper presents new near infrared observations of 160 Irregular variables of type Lb in the JHKL'M filter bands. These measurements are supplemented by data for additional 56 stars taken from the literature. In total 220 datasets are available because of some multiple observations. From our sample, 216 stars have near infrared (NIR) photometry

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