We have computed the Galactic Habitable Zones (GHZs) of the Andromeda galaxy (M31) based on the probability of terrestrial planet formation, which depends on the metallicity (Z) of the interstellar medium, and the number of stars formed per unit surface area. The GHZ was obtained from a chemical evolution model built to reproduce a metallicity

Aims: We present the abundance analysis of 12 planetary nebulae ionized by [WC]-type stars and weak-emission-line stars (wels) obtained from high-resolution spectrophotometric data. Our main aims are to determine the chemical composition of the nebulae and to study the behaviour of the abundance discrepancy problem (ADF) in this type of planetary

IRAS 01005+7910 is a carbon-rich protoplanetary nebula with a recently reported detection of mid-IR vibrational transitions of the fullerene C60 by Zhang and Kwok. We present new high spectral resolution (R ~ 57, 000) observations of this object obtained at the 3.6 m Telescopio Nazionale Galileo, showing the presence of two absorption bands at 9577

We present a determination of the average space density and birth rate of hydrogen-line (DA) white dwarfs within a radius of 1 kpc around the Sun, based on an observational sample of 360 candidate white dwarfs with g 19.5 and (g - r) 0.4, selected from the UV-Excess (UVEX) survey of the northern Galactic plane, in combination with a theoretical

We report the discovery of a candidate brown dwarf (BD) or a very low mass stellar companion (MARVELS-5b) to the star HIP 67526 from the Multi-object Apache point observatory Radial Velocity Exoplanet Large-area Survey (MARVELS). The radial velocity curve for this object contains 31 epochs spread over 2.5 yr. Our Keplerian fit, using a Markov Chain

The propagation of a shock wave into a medium is expected to heat the material beyond the shock, producing noticeable effects in intensity line ratios such as [O iii]/Hα. To investigate the occurrence of shocks in planetary nebulae (PNe), we have used all narrow-band [O iii] and Hα images of PNe available in the HST archive to build their [O iii]