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.

  • Figure caption: Data of LMC extreme stars are shown as solid, grey circles in the Spitzer color-magnitude diagram ([3.6]-[8.0] vs. [8.0]). The position of the models during the AGB evolution are also shown (where different colors correspond to different s
    For the first time we use self-consistent evolutionary models of low-and intermediate-mass stars (1-8 solar masses) coupled with theoretical dust formation models to follow the evolution of these stars during the Asymptotic Giant Branch (AGB) in the Spitzer Space Telescope two-color and color-magnitude diagrams. These models are the first able to identify the main regions in the Spitzer diagrams occupied by AGB stars in the Large Magellanic Cloud (LMC). The main diagonal sequences traced by LMC extreme stars in the two-color and color-magnitude Spitzer diagrams are nicely fit by carbon stars
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  • Figure caption: Simulation of the ultraluminous X-Ray source ULX P13. Crédits: Image created by Tom Russell (ICRAR) using the software created by Rob Hynes (Louisiana State University).
    Three decades ago one of the first astronomical satellites designed toobserve X-rays detected a new type of object: it had a much higher luminosity than any star, but much lower than other types of identified sources, such as the nuclei of active galaxies. They were dubbed, in a not very imaginative way, ultraluminous X rays (ULX) sources. Even recently we were still not really sure what they are. In this work, we have managed to solve this mystery and we have found that the mechanism which produces such a large luminosity in the most thoroughly studied ULX is not, as many had hoped, an
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  • Figure caption: Simulation of the magnetic field distribution (represented by lines whose lengths are proportional to the field strength) in a “cool” white dwarf. The darker zone is a cooler region where the intense magnetic field has partially blocked th
    Isolated cool white dwarf stars more often have strong magnetic fields than young, hotter white dwarfs which has been a puzzle because magnetic fields are expected to decay with time but a cool surface suggests that the star is old. In addition, some white dwarfs with strong fields vary in brightness as they rotate, which has been variously attributed to surface brightness inhomogeneities similar to sunspots, chemical inhomogeneities  and other magnetooptical effects. Here we describe optical observations of the brightness and magnetic field of the cool white dwarf WD1953-011 taken over
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  • Tc slopes versus ages for the full sample (top panel) and for the solar analogs (bottom panel). Gray solid lines provide linear fits to the data points.
    We explore a sample of 148 solar-like stars to search for a possible correlation between the slopes of the abundance trends versus condensation temperature (known as the Tc slope) with stellar parameters and Galactic orbital parameters in order to understand the nature of the peculiar chemical signatures of these stars and the possible connection with planet formation. We find that the Tc slope significantly correlates (at more than 4σ) with the stellar age and the stellar surface gravity (see Figure 1). We also find tentative evidence that the Tc slope correlates with the mean
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  • Figure caption: This is the spectrum of a massive AGB star (white dots) together with the predictions of the new model atmospheres (yellow line), and of the previous models which did not include the envelope (blue line). The Rubidium is detected as a very
    Intermediate mass stars, in their last phases of evolution ("AGB stars"),produce a large number of heavy elements (rich in neutrons), some ofthem radioactive isotopes, such as Rubidium and Technetium. Theseelements are pushed outwards to the surface of the star, and afterwards released into the interstellar medium. Among this type of stars, those least studied have been the more massive ones (between 4 and 8 times the mass of the Sun). Massive AGB stars have been recently identified in our Galaxy and in other nearby galaxies, such as the Magellanic Clouds, thanks to the detection of strong
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