Using a near-infrared stellar library of 706 stars with a wide coverage of atmospheric parameters, we study the behaviour of the CaII triplet strength in terms of effective temperature, surface gravity and metallicity. Empirical fitting functions for recently defined line-strength indices, namely CaT*, CaT and PaT, are provided. These functions can

Not Available

As a parallel result of an IT Project aimed at determining accurate distances to more than 30 planetary nebulae using the extinction-distance method, we report here the serendipitous discovery of a giant halo around NGC 7027. We obtained the spectra of more than 60 field stars around each PN with the LDSS multi-slit spectrograph at the 4.2-m

We present four lines of evidence leading to the conclusion that a notable fraction of the ionizing photon emission from the stars within H II regions in the disks of normal galaxies escapes from the regions into the surrounding galaxy and beyond. These are: (1) The surface brightness intensity distribution of the diffuse ensuremath {{Hα }} emitted

We present ultrahigh-resolution spectra for a set of nearby F-G-K stars on, or close to, the main sequence. The wavelength shifts of stellar lines relative to their laboratory wavelengths are measured for more than a thousand Fe I lines per star, finding a clear correlation with line depth. The observed patterns are interpreted as convective

When evolutionary synthesis models take into account the stochastic nature of the IMF together with the discrete number of stars in real stellar clusters, typical output turns to dispersion bands (where real data can be placed) instead of narrow lines. We present here a qualitative analysis of such dispersion in the SN rate, the kinetic energy and