Umbral flashes are sudden brightenings commonly visible in the core of some chromospheric lines. Theoretical and numerical modeling suggests that they are produced by the propagation of shock waves. According to these models and early observations, umbral flashes are associated with upflows. However, recent studies have reported umbral flashes in downflowing atmospheres. We aim to understand the origin of downflowing umbral flashes. We explore how the existence of standing waves in the umbral chromosphere impacts the generation of flashed profiles. We performed numerical simulations of wave

We detect a transiting rocky planet with an orbital period of 1.467 days around the nearby red dwarf star Gliese 486. The planet Gliese 486 b is 2.81 Earth masses and 1.31 Earth radii, a composition similar to that of Venus or Earth, as determined from exquisite radial velocity data and photometric light curves. The host star is at a distance of 26 light-years, very bright, and observable from both hemispheres of Earth. The stellar and planet properties indicate that despite the hot surface temperatures it is possible that the planet conserved part of its original atmosphere, making it an

Can neural networks distinguish computer simulated galaxy images from observed galaxies? This is the question that has been addressed in this work. For years, reproducing the morphological diversity of galaxies has been a problem for cosmological simulations. The new generation of simulations, such as Illustris TNG, are becoming more and more realistic. But enough to fool a neural network? In this work it is shown that it does not. Using unsupervised deep generative models, it is shown that, despite the fact that realism increases greatly in the last generation of simulations and with

The solar chromosphere is the region between the relatively thin and cold photosphere (temperature of a few thousand degrees) and the hot and extended corona (temperatures above a million degrees). Although the chromosphere is much less hot than the corona, it is also significantly denser and thus much more energy is required to sustain it. Moreover, the mechanical energy necessary to heat the corona needs to traverse the chromosphere, making it a crucial interface region to understand how this energy propagates and is released in the most violent activity of the solar upper atmosphere