In this paper, we present a study of the abundances of Si, Ca, Sc, Ti, V, Cr, Mn, Co, and Ni in a large set of stars known to harbor giant planets, as well as in a comparison sample of stars not known to have any planetary-mass companions. We have checked for possible chemical differences between planet hosts and field stars without known planets

We have obtained a new, deep, wide-field optical imaging survey of the young Alpha Persei cluster which reveals a well-populated lower main sequence extending into the substellar mass regime. Subsequent infrared photometry confirms that most of the candidate brown dwarfs are indeed likely to be cluster members, with a predicted minimum mass of

We present clear evidence for the motion of the companion star in the low-mass X-ray binary (LMXB) X1822-371. We detect N III λ4640 emission moving in antiphase with the radial velocity curve of the neutron star and produced on the X-ray-heated hemisphere of the donor star. From the motion of this feature we derive a lower limit to the radial

If the connection between the fundamental theory and neutrino mass matrices M_ u is sufficiently complicated all traces of underlying symmetries might be erased and an 'anarchical' M_ u, with random entries, can arise. It has been claimed that such random matrices generically prefer large mixing making unnecessary to invoke flavour symmetries to

This paper presents the results of a high-resolution imaging survey, using both ground-based and Hubble Space Telescope images, of a complete sample of nearby barred S0-Sa galaxies in the field, with a particular emphasis on identifying and measuring central structures within the bars: secondary bars, inner disks, nuclear rings and spirals, and off

We present the preliminary results of a programme aimed at defining a low-resolution near-infrared spectral classification scheme for faint M, L, and T-dwarfs. The method is based on the global shape of R˜100 complete near-infrared spectra from 0.8 to 2.4μm as obtained through a high-throughput prism-based optical element, the Amici device, mounted