We report on the discovery of a free-floating methane dwarf toward the direction of the young star cluster σ Ori. Based on the object's far-red, optical, and near-infrared photometry and spectroscopy, we conclude that it is a possible member of this association. We have named it S Ori J053810.1-023626 (S Ori 70 is the abridged name). If it is a

We present the results of a high spectral resolution (lambda / Delta lambda = 49 000) study of the circumstellar (CS) gas around the intermediate mass, pre-main sequence star UX Ori. The results are based on a set of 10 échelle spectra covering the spectral range 3800-5900 Å, monitoring the star on time scales of months, days and hours. A large

The soft X-ray transient GU Mus has been detected by XMM-Newton in the quiescent state. The source is very faint, with a 0.5-10.0 keV unabsorbed flux of =~ 1.1 x 10-14 ergs cm-2 s-1. The spectra is well fit by an absorbed powerlaw with a photon index of alpha = 1.6 +/- 0.4, close to the value seen when the source was in the low/hard state in Aug

We consider the process $mu o u_{e}ear{ u}_{mu} $in the framework of a two Higgs doublet model with flavor changing neutral currents (FCNC). Since FCNC generates in turn flavor changing charged currents in the lepton sector, this process appears at tree level mediated by a charged Higgs boson exchange. From the experimental upper limit for this

Analyses of the abundances of neutron-capture elements have led to the belief that these elements in metal-poor stars are r-process products with relative abundances closely resembling those found in the Solar system. This picture was challenged by Magain, who found that a pure r-process mix of the barium isotopes was inconsistent with the mix of

We discuss the effects of microlensing on the broad emission lines (BELs) of QSOs in the light of recent determinations of the size of the broad-line region (BLR) and its scaling with QSO luminosity. Microlensing by star-sized objects can produce significant amplifications in the BEL of some multiple-imaged QSOs, and could be very relevant for high