A statistical study of the decay of sunspots and sunspot groups is carried out using data contained in the Greenwich Photoheliographic Results. The period studied spans more than six decades, namely from 1874 to 1939. The adequacy of exponential, quadratic and linear decay laws to the area decay data is considered. The dependence, or otherwise, of

Seismology of single δ Scuti stars has mainly been inhibited by failing to detect many of the theoretically predicted pulsation modes, resulting in difficulties with mode identification. Theoretical and observational advances have, however, helped to overcome this problem, but the following questions then remain: do we know enough about the star to

Context. According to the current cosmological paradigm, large scale structures form hierarchically in the Universe. Clusters of galaxies grow through a continuous accretion of mass, and the presence of cluster substructures can be interpreted as signature of this process. Nevertheless, the rate and manner of mass accretion events are still matters

Visual and infrared light curves of the noncontact, short period, close binary system UR Tauri were obtained in 1992 November. A new ephemeris of the binary is given using the times of minima inferred from all the observations of the system to date. New light and photometric data from the analysis of the B, V and J,K light curves via the Wilson

We will present results of a survey of Hilda asteroids to look for extreme shape objects. We used WISE [1, 2] sparse IR photometry to identify objects with high photometric variability in different bands. Highly variable candidates were targeted by densely sampled, follow-up ground-based photometry. Similar strategies were successfully used to

EK Cep is a double-lined eclipsing binary system with unique characteristics. Accurate absolute dimensions are available, a good determination of the surface lithium abundance has been made, the system is known to show apsidal motion variations, and its secondary component seems to be in the pre main sequence phase. Due to all this, it appears to