A statistical study of the decay of sunspots and sunspot groups is carried out using data contained in the Greenwich Photoheliographic Results. The period...

An analysis has been carried out of the center-to-limb variation of the apparent sizes of the umbra, penumbra, and whole spot. It has revealed that the umbral...

During magnetopause crossings, the AMPTE CCE satellite frequently observed flux transfer events (FTEs) characterized by fluctuations in the magnetic field...

Blazars optical emission is generally dominated by relativistic jets, although the host galaxy, accretion disc, and broad-line region (BLR) may also contribute...

CCD surface photometry of the radio galaxy B2 0034+25 is reported. Fourier analysis of the intensity variations along a set of closely spaced elliptical...

Over the past two decades, helioseismology has revolutionized our understanding of the interior structure and dynamics of the Sun. Asteroseismology will soon...

Context. Stellar occultation is a powerful technique that allows the determination of some physical parameters of the occulting object. The result depends on...

We report the discovery of a stellar overdensity 8° north of the centre of the Small Magellanic Cloud (SMC; Small Magellanic Cloud Northern Over-Density; SMCNOD...

Stellar ejecta gradually enrich the gas out of which subsequent stars form, making the least chemically enriched stellar systems direct fossils of structures...