We present high-resolution spectroscopic observations of the quiet-Sun center-to-limb variations (CLV) of the He I triplet at 10 830 Å and the nearby Si I 10 827 Å line, observed with GREGOR Infrared Spectrograph (GRIS) and the improved High-resolution Fast Imager (HiFI+). The observations cover the interval μ = [0.1, 1.0], where μ is the cosine of

We present a detailed analysis of Terz V 2513 (=2MASS J17334728-2719266), a poorly studied symbiotic star. Our motivation was a peculiar beating pattern in its light curves from all-sky surveys and our own observations. Using Gaia DR3 and OGLE-IV photometry, we show that this variability arises from blending with a nearby, unrelated Mira variable

AT2025ulz is an optical/near-infrared transient discovered during follow-up of the candidate gravitational wave (GW) event S250818k. Its young age (≲1 day), rapid decline, and strong color evolution over the first 48 hr classify it as a potential kilonova candidate. In this work, we present the results of our observing campaign, carried out with

Stellar streams are sensitive to perturbations from, for example, giant molecular clouds, bars and spiral arms, infalling dwarf galaxies, or globular clusters which can imprint gaps, clumps, spurs, and asymmetries in tails. In addition to these effects, the impact of a major galactic merger on a population of stellar streams remains to be explored

Context. The photospheric Evershed flow is normally oriented radially outward, yet sometimes opposite velocities are observed not only in the chromosphere but also in the photospheric layers of the penumbra. Aims. We studied the velocity field in a special case of an active region with two mature sunspots, the lesser of which formed several days

Context.Gaia Data Release 3 (DR3) has revealed new massive runaway stars and large spectroscopic surveys have now enable detailed characterization studies. However, the relative contributions of binary supernova (BSS) and dynamical ejection (DES) scenarios to explain their runaway origin remain poorly constrained, particularly in the Milky Way