V4641 Sgr is a low-mass black hole X-ray binary system with somewhat puzzling spectral characteristics during its soft state. Recent high-resolution spectroscopic studies of V4641 Sgr have revealed strong ionized emission-line features in both the optical and X-ray bands, including P-Cygni signatures, and an unusually low soft-state luminosity

Exoplanets classified as super-Earths are commonly observed on short-period orbits, close to their host stars, but their abundance on wider orbits is poorly constrained. Gravitational microlensing is sensitive to exoplanets on wide orbits. We observed the microlensing event OGLE-2016-BLG-0007, which indicates an exoplanet with a planet-to-star mass

There is now a large sample of stars observed by the Kepler satellite with measured rotation periods and photometric activity index S ph. We use this data, in conjunction with stellar interiors models, to explore the interplay of magnetism, rotation, and convection. Stellar activity proxies other than S ph are correlated with the Rossby number, Ro

We report the first detections of [Ne v] λ14.3 μm and [Ne VI] λ7.7 μm at high confidence (S/N ≥ 6) in the nuclear region of the nearby spiral galaxy M83. Emission-line maps of these high-ionization lines show several compact structures. Specifically, the [Ne VI] emission is located at 140 pc from the optical nucleus and appears as a point source of

The destructive power of an impacting asteroid is primarily estimated by knowledge of its size. Asteroid 2024 YR4 reached a peak 2032 impact probability with Earth of 3%, motivating a desire to determine its size. Owing to its infrared capabilities, JWST is uniquely suited for such assessment, especially for decameter-scale objects. We used JWST to

We report the discovery of a large substructure in the Milky Way passing through the solar neighborhood, detected in actions calculated from Gaia DR3 data. We perform extensive tests to evaluate the selection effects present in the sample and conclude that they cannot produce an artifact with the same characteristics. This substructure, which we