We reexamine a 50+ yr old problem of deep central reversals predicted for strong solar spectral lines, in contrast to the smaller reversals seen in observations. We examine data and calculations for the resonance lines of H I, Mg II, and Ca II, the self-reversed cores of which form in the upper chromosphere. Based on 3D simulations, as well as data

We investigate the relations between the properties of bars and their host galaxies in a sample of 77 nearby barred galaxies, spanning a wide range of morphological types and luminosities, with 34 SB0-SBa and 43 SBab-SBc galaxies. The sample includes all the galaxies with reliable direct measurement of their bar pattern speed based on long-slit or

Aims: We aim to conduct an assessment of the demographics of substructures in cosmological simulations to identify low-mass stellar systems at high redshift, with a particular focus on globular cluster (GC) candidates. Methods: We explored a suite of high-resolution cosmological simulations from the First Billion Years Project (FiBY) at z ≥ 6. All

Context. One of the main atmospheric features in exoplanet atmospheres, detectable both from ground- and space-based facilities, is Rayleigh scattering. In hydrogen-dominated planetary atmospheres, Rayleigh scattering causes the measured planetary radius to increase toward blue wavelengths in the optical range. Aims: We aim to detect and improve

We report on the discovery of a transiting Earth-sized (0.95R ⊕) planet around an M3.5 dwarf star at 57 pc, EPIC 249631677. The planet has a period of ∼3.14 days, i.e., ∼π, with an installation of 7.45 S ⊕. The detection was made using publicly available data from K2's Campaign 15. We observed three additional transits with SPECULOOS Southern and