Aims.With strong evidence of fast and slow magnetoacoustic modes arising in the solar atmosphere there is scope for improved determinations of coronal parameters through coronal seismology. Of particular interest is the ratio P1/2P2 between the period P1 of the fundamental mode and the period P2 of its first harmonic; in an homogeneous medium this

The results of the determination of magnetic field strength and flux from weak polarimetric signals in solar inter-network regions are contradictory. We investigate the origin of this contradiction with the help of MHD simulations. It is shown that the Stokes-V line ratio of the Fe I 5247/5250 Å and 15652/15648 Å line pairs is a good indicator of

Results of photometric surveys have brought to light the existence of a population of giant planets orbiting their host stars even closer than the hot Jupiters (HJ), with orbital periods below 3 days. The reason why radial velocity surveys were not able to detect these very-hot Jupiters (VHJ) is under discussion. A possible explanation is that

We present numerical simulations of magnetoacoustic wave propagation from the photosphere to the low chromosphere in a magnetic sunspot-like structure. A thick flux tube, with dimensions typical of a small sunspot, is perturbed by a vertical or horizontal velocity pulse at the photospheric level. The type of mode generated by the pulse depends on

Aims.In this paper we aim to determine the longest pulsation period of infrared carbon stars. Methods: .Forty-seven infrared carbon stars were selected based on (1) IRAS colours and spectral classification from the IRAS LRS atlas, and (2) known carbon stars with large CO expansion velocities. Multi-epoch JHKL'photometry was obtained. Results:

Context: .GRB 050730 is a long duration high-redshift burst (z=3.967) that was discovered by Swift. The afterglow shows variability and was well monitored over a wide wavelength range. We present comprehensive temporal and spectral analysis of the afterglow of GRB 050730 including observations covering the wavelength range from the millimeter to X