The large amount of mass and angular momentum carried by disc winds makes them key processes to understand accretion onto compact objects, such as black holes and neutron stars. Here we present the discovery of an optical accretion disc wind in the X-ray transient Swift J1858.6-0814, a new binary system discovered in late 2018. Our 90-spectrum data set, taken with the 10.4 m Gran Telescopio Canarias (GTC), reveals the presence of conspicuous P-Cyg profiles in optical lines of helium and hydrogen. The evolution of these features indicates significant variations in the wind velocity, between a

Ultrahot giant exoplanets receive thousands of times Earth’s insolation. Their high-temperature atmospheres (greater than 2,000 kelvin) are ideal laboratories for studying extreme planetary climates and chemistry. Daysides are predicted to be cloud-free, dominated by atomic species and much hotter than nightside. Atoms are expected to recombine into molecules over the nightside, resulting in different day and night chemistries. Although metallic elements and a large temperature contrast have been observed, no chemical gradient has been measured across the surface of such an exoplanet

Earlier this year, a team of astrophysicists has revealed new insights on an ancient collision that our galaxy the Milky Way underwent with another smaller galaxy called Gaia-Enceladus early in its history. However the details on how and when that collision happened are not precisely known. The study of a single bright star called nu Indi, for which data from the NASA mission TESS (Transiting Exoplanet Survey Satellite), the ESA Gaia mission, and ground-based observations were combined, led to better characterize this event. Indeed, by applying a novel approach based on asteroseismology

Sunspots are intense collections of magnetic fields that pierce through the Sun’s photosphere, with their signatures extending upwards into the outermost extremities of the solar corona. Cutting-edge observations and simulations are providing insights into the underlying wave generation, configuration and damping mechanisms found in sunspot atmospheres. However, the in situ amplification of magnetohydrodynamic waves, rising from a few hundreds of metres per second in the photosphere to several kilometres per second in the chromosphere, has, until now, proved difficult to explain. Theory