The abundance ratios between key elements such as iron and α-process elements carry a wealth of information on the star formation history (SFH) of galaxies. So far, simple chemical evolution models have linked [α/Fe ] with the SFH time-scale, correlating large abundance ratios with short-lived SFH. The incorporation of full spectral fitting to the analysis of stellar populations allows for a more quantitative constraint between [α/Fe ] and the SFH. In this letter, we provide, for the first time, an empirical correlation between [α/Fe ] (measured from spectral indices) and the SFH (determined

The authors show that the surface structure of the primitive asteroid (65) Cybele is covered by a layer of fine anhydrous silicate grains, mixed with smaller quantities of water ice and complex organics, similar to the nonequilibrium phases coexisting on comet surfaces. The co-existence of water ice and anhydrous silicates on the surface indicates that silicate hydration did not occurred, suggesting that the surface temperatures remained low. The team of researchers is the same that published last April two papers in Nature showing the first evidence of water ice and organic molecules on an

Central starbursts in galaxies are an extreme example of ongoing galaxy evolution. The outer parts of galaxies contain a fossil record ofgalaxy formation and evolution processes in the more distant past. The characterization of resolved stellar populations allows one a detailed study of these topics.In our study we used the Hubble Space Telescope to observe the outerparts (up to 8 scale radii) of NGC 1569 and NGC 4449, two of the closest and strongest dwarf starburst galaxies in the local universe, to characterize their stellar density and populations, and obtain new insights into the

Fibrils are thin elongated features visible in the solar chromosphere in and around magnetized regions. Because of their visual appearance they have been traditionally considered a tracer of the magnetic field lines. To our best knowledge, this common conception has never been actually put to test, probably because a proper empirical determination of the chromospheric magnetic field is very challenging, requiring high-resolution spectro-polarimetry in chromospheric lines. In this work we challenge that notion for the first time by comparing their orientation to that of the magnetic field

NGC 4013 is a nearby Sb edge-on galaxy known for its “prodigious” HI warp and its “giant” tidal stream. Previous work on this unusual object shows that it cannot be fitted satisfactorily by a canonical thin+thick disk structure. We have produced a new decomposition of NGC 4013, considering three stellar flattened components (thin+thick disk plus an extra and more extended component) and one gaseous disk. All four components are considered to be gravitationally coupled and isothermal. To do so, we have used the 3.6µm images from the Spitzer Survey of Stellar Structure in Galaxies (S4G).We

Nobel-prize winning scientists (2010), Andre Geim and Konstantin Novoselov, synthesized graphene in the laboratory in 2004. Just seven years later, this material of extraordinary strength, thinness and elasticity may have been found in space. The first evidence of the possible existence of C 24 - a flat two-dimensional molecule, one atom thick, possibly a "small piece of graphene - in space has been found. To confirm beyond a doubt that what has been detected is actually C 24, laboratory spectroscopy would have to be carried out, something which is practically impossible with current