We report the detection of a radial velocity companion to SDSS J091709.55+463821.8, the lowest mass white dwarf currently known, with M~0.17 Msolar. The radial velocity of the white dwarf shows variations with a semi-amplitude of 148.8+/-6.9 km s-1 and a period of 7.5936+/-0.0024 hr, which implies a companion mass of M>=0.28 Msolar. The lack of

Using deep NIR VLT ISAAC and optical HST WFPC2 imaging in the HDF-S and MS 1054-03, we study the rest-frame UV-to-optical colors and magnitudes of galaxies to z~3. Unlike the present day, there is no evidence for a red sequence at z~3, but there does appear to be a well-defined CMR for blue galaxies at all redshifts, with more luminous galaxies

Not Available

The star formation history (SFH) of Local Group galaxies is a powerful tool for studying their evolution, including chemical enrichment histories and stellar population gradients, which in turn may shed light on the role of reionization or Supernovae feedback in galaxy formation and evolution. In particular, isolated dwarfs are ideal laboratories

During Cycle 14 a total of 113 HST orbits were secured to observe five isolated dwarf galaxies, namely Tucana, LGS3, LeoA, IC1613, and Cetus. The aim of the project is a full characterization of the stellar content of these galaxies, in term of their SFH, radial distributions, halo populations and variable stars. Deep (V~29) F475W, F814W data

A-type asteroid (1951) Lick has a very red visible and near-infrared reflectance spectrum, and it is one of the reddest Near-Earth objects. Its surface is probably affected by heavy space weathering processes. We investigate the possibility of a weathering saturation regime. We compare Lick's spectrum with those of silicate olivine after laser