The quiet Sun (the 99%, or more, of the solar surface not covered by sunspots or active regions) is receiving increased attention in recent years; its role on the global magnetism and its complexity are being increasingly recognised. A picture of a rather stochastic quiet Sun magnetism is emerging . From these recent works, the quiet Sun magnetism is presented as a myriad of magnetic field vectors having an isotropical distribution with a cascade of scales down to the mean free path of the photon (1 marcsec, or 10km on the solar surface). But this chaotic representation also shows clear signs of intermittency: at a low frequency rate (0.022 events h-1 arcsec-2) the magnetic field appear in the quiet Sun forming well-organised loop structures at granular scales. Right figure shows an example of such small-scale loop (1 arcsec, or 1000 km on the solar surface). We cas see as it is formed by a myriad of nested field lines forming a spartial (and temporal) coherent structure. More interesting, these loops rise to higher layers (see left figure) and their energy input into the chromosphere can be important for the heating of this layer.
Advertised on
References
(2010)The Astrophysical Journal Letters, Volume 714, Issue 2, pp. L94-97
It may interest you
-
The transient Swift J1727.8-162 is the latest member of the X-ray binary black hole family to be discovered. They are formed by a black hole and a low-mass star whose gas is stripped off and accreted to the black hole via an accretion disc. The high temperature of the accretion disc makes it shine in all energy bands up to X-rays, and is particularly bright during epochs known as outbursts. In this novel study, published just a few months after the discovery of the system, we present 20 epochs of optical spectroscopy obtained with the GTC-10.4m telescope. The spectra cover the main accretionAdvertised on
-
There is increasing evidence that single-star evolutionary models are unable to reproduce all of the observational properties of massive stars. Binary interaction has emerged as a key factor in the evolution of a significant fraction of massive stars. In this study, we investigate the helium (Y(He)) and nitrogen surface abundances in a comprehensive sample of 180 Galactic O-type stars with projected rotational velocities of ≤150 km/s. We found a subsample (~20% of the total, and ~80% of the stars with Y(He) ≥ 0.12) with a Y(He) and nitrogen abundance combined pattern that is unexplainable byAdvertised on
-
The universality of the stellar initial mass function (IMF) is one of the most widespread assumptions in modern Astronomy and yet, it might be flawed. While observations in the Milky Way generally support an IMF that is invariant with respect to the local conditions under which stars form, measurements of massive early-type galaxies systematically point towards a non-universal IMF. To bridge the gap between both sets of evidence, in this work we measured for the first time the low-mass end of the IMF from the integrated spectra of a Milky Way-like galaxy, NGC3351. We found that the slope ofAdvertised on