We report on intermediate-to-high resolution spectroscopy and standard broadband photometry of late-type visual companions to early-type stars. Our program...

The very high surface gravity and low temperature of PHL 932, a hot subluminous star surrounded by a planetary nebula, imply that it cannot be a post-AGB star...

We present a study of the lithium abundance of five pre-main sequence (PMS) double-lined binaries. These binaries are composed of weak-lined T Tauri stars...

Stars with wide brown dwarf companions that host exoplanets are extremely rare, as only four were reported to date. Different theories propose that planets can...

The present volume on stellar formation discusses basic physical principles relevant to such processes, regions of recent star formation, galaxy formation and...

The paper reports measurements of the integrated fluxes over the wavelength range 380 nm - 900 nm for 216 stars using a Reticon spectrometer in conjunction with...

The activity phase of BF Cygni discovered in May 1989 and which lasted about two years is examined. The UV emission lines, usually strong during quiescence...

We present an analysis of the binary central star of the planetary nebula NGC 2346 based on archival data from the International Ultraviolet Explorer, and new...

An observational test of the binary hypothesis for the origin of the blue straggler (BS) stars has been performed searching for radial velocity variables among...