Tag: macchie

The stellar surface trated as a puzzle. The study: “PAStar: a model for stellar surface from the Sun to active stars” of A. Petralia (INAF – OAPA) appeared on A&A

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In stars, a continuous tug-of-war unfolds between stellar plasma and the magnetic field. At stake is control over the local dynamics: the winner sets the rules that govern the local stellar properties. For instance, the photosphere of stars is generally quite homogeneous, except for granulation. However, in certain regions of the photosphere, the magnetic field can concentrate, intensify, and produce

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Spots and faculae in V1298 Tau. The paper: “Spot Modeling through Multiband Photometry Analysis of V1298 Tau” of A. Biagini (INAF-OAPA/UNIPA) appeared on A&A

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Most stars behave like enormous dynamos, producing intense magnetic fields within them. These magnetic fields then interact with the plasma that constitutes the star’s interior and atmosphere, in a constant tug of war where the prevailing force dominates the dynamics. In the outer region of stars, from the photosphere to the corona, the pressure exerted by the gas is less

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The study: “Estimating Magnetic Filling Factors from Simultaneous Spectroscopy and Photometry: Disentangling Spots, Plage, and Network” of T. W. Milbourne (Harvard University), recently appeared on ApJ, present two new methods that allow astronomers to estimate the filling factor of magnetic active regions

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About 20% of the exoplanets discovered so far (October 2021) were found with measurements of radial velocity (data from https://exoplanets.nasa.gov/). This method is based on spectroscopic observations of stars with planets, from which it is possible to measure the Doppler effect produced by periodic oscillations of the star, due to the gravitational attraction between star and planet along the orbit of

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Photospheric spots and planetary transits. The study: “Correcting the effect of stellar spots on ARIEL transmission spectra” of G. Cracchiolo (UNIPA, INAF-OAPA) appeared on MNRAS

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A “transit” occurs when we observe a planet moving across the disc of its star. Thus, during the transit the planet obscures a small portion of its star, slightly reducing its luminosity. While in the Solar System the only planets we can observe transiting in front of the Sun are Mercury and Venus, transits is still the most efficient method

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