The recently discovered Virgo stellar overdensity, which extends over ~1000 deg2 perpendicular to the Galactic disk plane (7 kpc

Context: The structural properties of the low surface brightness stellar host in blue compact dwarf galaxies are often studied by fitting r1/n models to the outer regions of their radial profiles. The limitations imposed by the presence of a large starburst emission overlapping the underlying component makes this kind of analysis a difficult task

In this work we present support for recent claims that advocate a downward revision of the solar oxygen abundance. Our analysis employs spatially resolved spectropolarimetric observations including the Fe I lines at 6302 Å and the O I infrared triplet around 7774 Å in the quiet Sun. We used the Fe I lines to reconstruct the three-dimensional

In this work we present support for recent claims that advocate a downward revision of the solar oxygen abundance. Our analysis employs spatially-resolved spectro-polarimetric observations including the Fe I lines at 6302 Angstroms, and the O I infrared triplet around 7774 Angstroms, in the quiet Sun. We used the Fe I lines to reconstruct the three

A suitable diagnostic tool for investigating the magnetism of the solar chromosphere is the observation and theoretical modeling of the Hanle and Zeeman effects in solar spicules. In our presentation we highlighted the great scientific interest of this new diagnostic window by showing how the magnetic field vector can be inferred from

Extremely low mass white dwarfs are very rare objects likely formed in compact binary systems. We present MMT optical spectroscopy of 42 low-mass white dwarf candidates serendipitously discovered in a survey for hypervelocity B-type stars. One of these objects, SDSS J0917+46, has Teff=11,288+/-72 K and logg=5.48+/-0.03 with an estimated mass of 0