We present radial velocity follow-up obtained with ESPRESSO of the M-type star LTT 1445A (TOI-455), for which a transiting planet b with an orbital period of 5.4 days was detected by TESS. We report the discovery of a second transiting planet (LTT 1445A c) and a third non-transiting candidate planet (LTT 1445A d) with orbital periods of 3.12 and 24

Fast X-ray Transients (FXTs) are X-ray flares with durations ranging from a few hundred seconds to a few hours. Possible origins include the tidal disruption of a white dwarf by an intermediate-mass black hole, a supernova shock breakout, or a binary neutron star merger. We present the X-ray light curve and spectrum as well as deep optical imaging

We present a photometric study of the resolved stellar populations in Andromeda IX (And IX), the closest satellite to M31, a metal-poor and low-mass dwarf spheroidal galaxy. We estimate a distance modulus of ${24.56}_{-0.15}^{+0.05}$ mag based on the tip of the red giant branch. By probing the variability of asymptotic giant branch stars, we study

This paper presents a theoretical investigation of the polarization and magnetic sensitivity of the near-ultraviolet (near-UV) solar spectral lines of Fe II between 250 and 278 nm. In recent years, UV spectropolarimetry has become key to uncovering the magnetism of the upper layers of the solar chromosphere. The unprecedented data obtained by the

Context. While it is conjectured that a chromospheric canopy plays a role in penumbra formation, it has been difficult to find observational evidence of the connectivity between the photosphere and the chromosphere. Aims: We investigate the existence of a chromospheric canopy as a necessary condition for the formation of a penumbra. Another aim is

Context. Quaoar is a classical trans-Neptunian object (TNO) with an area-equivalent diameter of 1100 km and an orbital semi-major axis of 43.3 astronomical units. Based on stellar occultations observed between 2018 and 2021, an inhomogeneous ring (Q1R, i.e., Quaoar's first ring) has been detected around this body. Aims: A new stellar occultation by