Spectroscopy of asteroids can be diagnostic of their surface composition and other properties such as internal structure. The European Space Agency's Gaia mission will result in a dramatic increase in the number and quality of asteroid spectra in the 0.35–0.9 μm wavelength range. This homogeneous set of spectra, with high sensitivity in the near

The prototype SONG node, SONG-OT, is currently being installed and tested at Observatory del Teide on Tenerife. SONG will be a global network of 1-m robotic telescopes, equipped with a high-resolution échelle spectrograph and dual-colour lucky imaging cameras. The network will be devoted to the seismic study of bright stars and characterisation of

Aims: We investigate the impact on Fe abundance determination of including magnetic flux in series of 3D radiation-magnetohydrodynamics (MHD) simulations of solar convection, which we used to synthesize spectral intensity profiles corresponding to disc centre. Methods: A differential approach is used to quantify the changes in theoretical

The composition of the most primitive solar system condensates, such as calcium-aluminum-rich inclusions (CAIs) and micron-sized corundum grains, show that short-lived radionuclides (SLR), e.g., 26Al, were present in the early solar system. Their abundances require a local or stellar origin, which, however, is far from being understood. We present

Context. The surface layers of the Sun are strongly stratified. In the presence of turbulence with a weak mean magnetic field, a large-scale instability resulting in the formation of nonuniform magnetic structures, can be excited on the scale of many (more than ten) turbulent eddies (or convection cells). This instability is caused by a negative

We report the result of a new Chandra observation of the black hole X-ray transient H 1705-250 in quiescence. H 1705-250 was barely detected in the new ˜50 ks Chandra observation. With five detected counts, we estimate the source quiescent luminosity to be LX ˜ 9.1 × 1030 erg s-1 in the 0.5-10 keV band (adopting a distance of 8.6 kpc). This value