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.

  • Temporal evolution of the spiral wavefront observed in a sunspot photosphere.
    There are many oscillatory phenomena in the Sun which show up from the deepest interior layers to the outermost layers of its atmosphere. The study of these waves is a fundamental problem in solar physics, since they are one of the candidates proposed to explain the high temperatures measured in the chromosphere and the corona of the Sun, and they are used to characterize the structure of the Sun using seismological analyses. In this work we have studied wave propagation in sunspots. Sunspots are caused by strong concentrations of magnetic field, visible on the solar disc as dark regions
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  • Li abundance, A(Li), versus metallicity, [Fe/H], of the extremely iron-poor dwarf star J0023+0307 compared with other dwarf stars (logg ≥ 3.7) with Li abundance values from Bonifacio et al. (2018) and references therein. Blue filled circles connected with a solid line indicates the spectroscopic binary systems in González Hernández et al. (2008) and Aoki et al. (2012). The Lithium “plateau” (also called Spite Plateau) reference is shown as a solid line at a level of A(Li) = 2.20 dex. Blue dashed line repres
    We present an analysis of the UVES high-resolution spectroscopic observations at the 8.2m VLT of J0023+0307, an extremely iron-poor dwarf star. We are unable to detect iron lines in the spectrum but derive [Fe/H]< −6.1 from the Ca II resonance lines assuming [Ca/Fe]=0.40. The chemical abundance pattern of J0023+0307, with very low [Fe/Mg] and [Ca/Mg] abundance ratios, but relatively high absolute Mg and Si abundances, suggests J0023+0307 is a second generation star formed from a molecular cloud polluted by only one supernova in which the fall-back mechanism played a role. We measure a carbon
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  • Credit: ALMA (ESO/NAOJ/NRAO)/Decin et al. (2019).
    Towards the end of their lives some 95% of stars evolve into red giants which lose their mass via a “stellar wind”. Eventually they end up as planetary nebulae, ionized gas with a central hot star, a white dwarf. Here we report ALMA data on massive red giant (asymptotic giant branch, AGB) stars, displaying a spiral structure which show that these stars are not individual and have a binary companion. This offers an alternative explanation to the high rates of mass loss which it was thought were present towards the end of the lives of the most massive AGB stars. We show that these stars lose
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