Aims: An in depth analysis of the images acquired in broad-band optical and infrared observations in the R, I, and J, H, Ks bands of comet C/199T1 (McNaught-Hartley) acquired from Jan. 26 to Feb. 05, 2001 has been performed and is presented here. Methods: Beside the Laplace filtering technique applied to enhance structures in the dust coma of the

The stability of C60 and C70 fullerenes in the interstellar medium deposited on dust surface or embedded in meteorites and comets has been simulated with γ irradiation and with He+ ion bombardment. It is shown by vibrational spectroscopy that a γ radiation dose of 2.6MGy (1Gy = 1 joule absorbed energy per kilogram) causes partial oligomerization of

We report 2D time-dependent non-linear magneto-hydrodynamical simulations of waves in the atmospheres of roAp stars. We explore a grid of simulations in a wide parameter space. The aim of our study is to understand the influence of the atmosphere and the magnetic field on the propagation and reflection properties of magneto-acoustic waves

Context: There is now growing evidence that some brown dwarfs (BDs) have very strong magnetic fields, and yet their surface temperatures are so low that the coupling is expected to be small between the matter and the magnetic field in the atmosphere. In the deeper layers, however, the coupling is expected to be much stronger. Aims: This raises the

We present RICO, a code designed to compute the ionization fraction of the universe during the epoch of hydrogen and helium recombination with an unprecedented combination of speed and accuracy. This is accomplished by training the machine learning code PICO on the calculations of a multilevel cosmological recombination code which self-consistently

We propose to observe Cyg X-1, an accreting black hole, and Sco X-1, an accreting neutron star, with a 2-hour long uninterrupted exposure each with IRAC in high time resolution modes. Their rapidly variable IR components are likely to come from relativistic jets, and these data will provide important insights into how these jets are powered by the