Transmission spectroscopy, a method for studying exoplanetary atmospheres by measuring the wavelength-dependent radius of a planet as it transits its star, relies on a precise understanding of the spectrum of the star being occulted. However, stars are not homogeneous, constant light sources but have temporally evolving photospheres and

Stellar dynamos generate magnetic fields that are of fundamental importance to the variability and evolution of Sun-like and low-mass stars, and for the development of their planetary systems. As a key to understanding stellar dynamos, empirical relations between stellar parameters and magnetic fields are required for comparison to ab initio

We present the most extensive and well-sampled long-term multiband near-infrared (NIR) temporal and spectral variability study of OJ 287, considered to be the best candidate binary supermassive black hole blazar. These observations were made between 2007 December and 2021 November. The source underwent ~2-2.5 mag variations in the J, H, and Ks NIR

CHOCOLATE is a novel Chromatic Line-Profile Tomography technique that has been recently developed and presented to the community as an alternative approach for recovering the broadband transmission spectrum of transiting exoplanets from high-resolution spectroscopy. This methodology is based on the spectral line-profile distortions produced by a

Context. The timescale of a microlensing event scales as a square root of a lens mass. Therefore, long-lasting events are important candidates for massive lenses, including black holes. Aims: Here, we present the analysis of the Gaia18cbf microlensing event reported by the Gaia Science Alerts system. It exhibited a long timescale and features that

Aims: The high-magnification microlensing event KMT-2021-BLG-1077 exhibits a subtle and complex anomaly pattern in the region around the peak. We analyze the lensing light curve of the event with the aim of revealing the nature of the anomaly. Methods: We test various models in combination with several interpretations: that the lens is a binary