We present the results of radio observations of the black hole binaries GRO J1655-40 and XTE J1550-564 in quiescence, with the upgraded Australia Telescope Compact Array. Neither system was detected. Radio flux density upper limits (3σ) of 26 μJy (at 5.5 GHz), 47 μJy (at 9 GHz) for GRO J1655-40 and 1.4 mJy (at 1.75 GHz), 27 μJy (at 5.5 GHz), 47 μJy

Through the observational study of stellar pulsations, the internal structure of stars can be probed and theoretical models can be tested. The main sequence γ Doradus (Dor) and δ Scuti (Sct) stars with masses 1.2-2.5 M&sun; are particularly interesting for asteroseismic study. The γ Dor stars pulsate in high-order gravity (g) modes, with

The spectrum of O and B Supergiants is known to be affected by an important extra line-broadening (usually called macroturbulence) that adds to stellar rotation. Recent analysis of high resolution spectra has shown that the interpretation of this line-broadening as a consequence of large-scale turbulent motions would imply highly super-sonic

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We report the results from a photometric and spectroscopic survey of ˜1.4 deg2 of the young open cluster IC 2602. Fourteen objects have been identified as having magnitudes, spectral types and radial velocities consistent with being probable or possible low-mass stellar members of the cluster. We have used the observed location of the lithium

We present the results of a spectroscopic campaign on the early-type double-lined binary HD 64315. The radial velocity curve was calculated using a fit to model atmospheres, considering two components. After this, we find strong evidences suggesting that HD 64315 is composed of two binary systems, one of them eclipsing. We re-analyse HD 64315