This paper presents a homogeneous study of abundances in a sample of 79 northern Galactic planetary nebulae (PNe) whose morphological classes have been uniformly determined. Ionic abundances and plasma diagnostics were derived from selected optical line strengths in the literature, and elemental abundances were estimated with the ionization

We detect some objects that can be classified as planetary nebulae candidate s (PNc), using images of a southern region of M 33. This search is the deepest one made up to now in M 33. The search was made with narrow band filters centered on [O III], Hα and adjacent continua. We detect 48 PNc, from which 16 have a ratio of [O III]-to-Hα fluxes

Aims.We present a search for low-mass brown dwarfs in the Pleiades open cluster. The identification of Pleiades members fainter and cooler than those currently known allows us to constrain evolutionary models for L dwarfs and to extend the study of the cluster mass function to lower masses. Methods: .We conducted a 1.8 deg2 near-infrared J-band

Context. The general properties (e.g., activity class, star formation rates, metallicities, extinctions, average ages, etc.) of luminous (LIRGs) and ultraluminous infrared galaxies (ULIRGs) in the local universe are well known because large samples of these objects have been the subject of numerous spectroscopic works over the past three decades

We present the very first results of a full spectropolarimetric study (in the four Stokes parameters I, Q, U and V) performed with NARVAL at TBL, on the Mira star o Cet. We focus on the high level of time variable linear polarization detected in Hydrogen emission lines.

We performed a detailed analysis of the use of [C/N] measured in red giant branch stars between the completion of the first dredge up and the red giant branch bump ([C/N] FDU) as age indicator. [C/N] FDU cannot give accurate ages for individual stars, but may provide a general chronology for the formation of composite populations and add