Elemental composition guides the formation, evolution, and atmosphere processes of the lowest-mass stars and brown dwarfs, or ultracool dwarfs (UCDs). While the vast majority of known UCDs are solar-metallicity objects in the Milky Way's thin disk, a rare subsample of metal-poor stellar and substellar subdwarfs are known in the Solar Neighborhood

A few remarkable examples of alternative cosmological theories are shown, ranging from a compilation of variations on the Standard Model (inhomogeneous universe, Cold Big Bang, varying physical constants or gravity law, zero-active mass, Milne cosmology, cyclical models), through the more distant quasi-steady-state cosmology, plasma cosmology, or

We present JWST NIRCam imaging targeting 13 z ~ 3 infrared-luminous (L IR ∼ 5 × 10 12L ⊙) galaxies from the ALESS survey with uniquely deep, high-resolution (0 . ″ 08–0 . ″ 16) Atacama Large Millimeter/submillimeter Array 870 μm imaging. The 2.0–4.4 μm (observed frame) NIRCam imaging reveals the rest-frame near-infrared stellar emission in these

A sub-Earth-mass planet orbiting Barnard's star, designated as Barnard b, has recently been announced. At almost the same time, the first photometric data of Barnard's star by the Transit Exoplanet Survey Satellite (TESS) was released in Sector 80. We explore the possibility of emergent transits of Barnard b in TESS photometry. The detrended 2 min

The AU Microscopii planetary system is only 24 Myr old, and its geometry may provide clues about the early dynamical history of planetary systems. Here, we present the first measurement of the Rossiter-McLaughlin effect for the warm sub-Neptune AU Mic c, using two transits observed simultaneously with the European Southern Observatory's (ESO's)

In main-sequence, low-mass (<1.3 Solar mass) stars, rotation and magnetic activity decrease over time, with the spin-down thought to be due to angular momentum lost through magnetized winds. This magnetic activity heats the stellar atmospheres, leading to the production of Hα, ultraviolet (UV), and X-ray radiation, each originating from different