We provide the first reference framework for extremely metal-poor (XMP) OB-type stars. We parsed a grid of 0.10 $Z_{\odot }$FASTWIND models, covering the parameter space of O stars and early-B supergiants, through contemporary spectral classification criteria to deliver a calibration of key stellar properties as a function of spectral type, and

HR 5907 (HD 142184) stands out among magnetic OB stars for its rapid rotation, exceptionally hard X-ray emission, and strong magnetic field. High-frequency (>5 GHz) radio emission from the star exhibits an approximately flat spectrum that can be attributed to gyrosynchrotron emission from a dense centrifugal magnetosphere. In a survey of radio

White dwarfs (WDs) are the most abundant compact objects, and recent surveys have suggested that over a third of WDs in accreting binaries host a strong (B ≳ 1 MG) magnetic field. However, the origin and evolution of WD magnetism remain under debate. Two WD pulsars, AR Sco and J191213.72–441045.1 (J1912), have been found, which are non-accreting

The detection of molecules on the coldest and outermost objects in our Solar System has long been limited by the terrestrial atmosphere and sensitivity of the available instrumentation. However, near-infrared observations by the James Webb Space Telescope have provided an unprecedented view of the molecular diversity on the surfaces of trans

We present the first X-ray polarization measurements of GX 339–4. IXPE observed this source twice during its 2023–2024 outburst, once in the soft-intermediate state and again during a soft state. The observation taken during the intermediate state shows a significant (4σ) polarization degree P X = 1.3% ± 0.3% and polarization angle θ X = ‑74° ± 7°

Some ultra diffuse galaxies (UDGs) reveal many more globular clusters (GCs) than classical dwarf galaxies of the same stellar mass. These UDGs, with a mass in their GC system ( $M_{\rm GC}$) approaching 10 per cent of their host galaxy stellar mass ( $M_{\ast }$), are also inferred to have high halo mass to stellar mass ratios ( $M_{\rm halo}/M_{