News

This section includes scientific and technological news from the IAC and its Observatories, as well as press releases on scientific and technological results, astronomical events, educational projects, outreach activities and institutional events.

  • Intensity profiles of an iron line calculated in a 3D hydrodynamical model of the atmosphere of a metal-poor star, assuming LTE (right panel) and without assuming LTE (left panel). The resulting average profile in each case is that given by thickest line.
    The abundances of oxygen and iron in metal-poor stars have been determined through non-LTE radiative transfer simulations in three-dimensional (3D) hydrodynamical models of their atmospheres. The performing of this type of calculations required to develop first very efficient numerical methods and computer programs. Taking into account that the atmospheres of the stars are 3D systems and the impact of non-LTE effects leads to very significant changes in the derived chemical abundances. It has been concluded that the metalicity of some metal-poor stars could be significantly larger than
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  • The extinction curve observed, compared with that of the LMC (solid line) and the Milky Way (dotted line).
    Using a gravitational lens, the first precise determination of the extinction curve from the optical to the far UV has been carried out in a galaxy outside the Local Group (a z=0,83). It has turned out to be approximately the same as that observed at the LMC and different from that of our galaxy. These studies reveal the properties of interstellar dust in distant galaxies (Mediavilla et al., 2005, ApJ 619, 749).
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  • Spectrum of the planetary nebula in the Sextans A galaxy obtained by the Very Large Telescope (VLT).
    Chemical abundances have been measured of PNe and HII regions in Sex A and Sex B, two galaxies located on the outskirts of the Local Group. These PNe are the farthest ones where such a direct abundance measurement has been obtained. PNe and HII regions in Sex B show unexpectedly similar abundances, suggesting a very low chemical enrichment. In Sex A there is only one PN known, and its anomalous chemistry is helping us to develop new models of stellar evolution in very low metallicity environments. Furthermore, new candidate PNe in NGC 6822 have been discovered, increasing the number of
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  • Relative frequency of the abundance of O compared to H in the study samples, using a variety of indicators.
    A study comparing the oxygen abundance of stars with planets to stars without planets has been completed. By looking at various indicators of the O abundance, it was discovered that stars with planets generally present higher oxygen abundances. These studies are part of an IAC programme to determine whether significant differences exist between the chemical compositions of stars with and without planets (Ecuvillon, Israelian et al., 2006, A&A 445, 633).
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  • Hace ya más de dos vueltas alrededor del Sol que caosyciencia empezó su andadura en la comunicación científica. Por fortuna, algunos habitantes de la Tierra continúan pensando que vale la pena seguir recibiendo gratuitamente este pequeño mundo habitado por artículos, animaciones, imágenes y vídeos, en el cual se explica un poco de todo, con un cierto favoritismo reconocido por la Astrofísica, no en vano es una iniciativa del Instituto de Astrofísica de Canarias (IAC). En este período insignificante en la escala del Universo, el rozamiento de caosyciencia con su entorno ha demostrado que no
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