The quiet Sun (the 99%, or more, of the solar surface not covered by sunspots or active regions) is receiving increased attention in recent years; its role on the global magnetism and its complexity are being increasingly recognised. A picture of a rather stochastic quiet Sun magnetism is emerging . From these recent works, the quiet Sun magnetism is presented as a myriad of magnetic field vectors having an isotropical distribution with a cascade of scales down to the mean free path of the photon (1 marcsec, or 10km on the solar surface). But this chaotic representation also shows clear

Thanks to the NASA’s Spitzer Space Telescope, bucket loads of large carbon molecules, the so-called fullerenes (C 60), have been found around dying stars in the Milky Way and in a nearby galaxy. The fullerenes – the biggest molecules known in space – have been detected accompanied by large concentrations of hydrogen, contradicting the actual theories and the laboratory experiments, which show that fullerene formation is strongly inhibited by hydrogen. It turns out that fullerenes are much more common and abundant in the Universe than initially thought, because these molecules have been

Using images of the Advanced Camera for Surveys" of the Hubble SpaceTelescope we have analyzed the global physical parameters of thepopulations of HII regions in two galaxies: M51 and NGC 4449. M51 is a large spiral, in which we have measured and catalogued the Halpha luminosities, the radii, and the positions of more than 2000 of its HIIregions, while NGC 4449 is a dwarf irregular, in which we have catalogued over 200 HII regions. From these measurements we have obtained the mean electron densities, and have derived two simple but powerful relations. The electron density n_e of an HII

In this work we present a recent study of the bar fraction in the ComaCluster galaxies based on a sample of ~190 galaxies selected from theSloan Digital Sky  Survey Data Release 6 and observed with the Hubble Space Telescope (HST)  Advanced  Camera for Survey  (ACS).The unprecedented resolution of the HST-ACS  images allows us  to explore the presence of bars, detected by visual classification, throughout luminosity range of 9 mag (-23 < Mr < -14), permitting us to study th poor known region  of dwarf galaxies. We find that  bars are hosted bygalaxies in  a tight range of both  luminosities

The Gran Telescopio CANARIAS open new prospects to characterise the oldest population of stars in our Galaxy with the discovery of a cold and distant low-metallicity star A new object with an age of thousands of millions of years and a mass of one tenth of the Sun, placing it at the frontier between low-mass stars and brown dwarfs, has been discovered as the furthest of its class in Milky Way. Nicknamed ULAS1350, this subdwarf could become on of the key element to improve our knowledge on the first steps of the formation of our Galaxy.The team of European astronomers responsible for the

A long-standing issue in solar astrophysics concerns the strength and structure variations with height of the magnetic field in the chromosphere of the quiet Sun. Our empirical knowledge on this issue has remained vague notwithstanding the qualitative information provided by high resolution monochromatic images of the solar atmosphere taken at various wavelengths across strong spectral lines like H-alpha showing a mass of cell-spanning fibrils as a flattened carpet, with upright ones jutting out from network patches. Unfortunately, such images do not provide quantitative information on the