The Kelvin-Helmholtz instability has been proposed as a mechanism to extract energy from magnetohydrodynamic (MHD) kink waves in flux tubes, and to drive dissipation of this wave energy through turbulence. It is therefore a potentially important process in heating the solar corona. However, it is unclear how the instability is influenced by the

We developed a new approach to provide accurate estimates of the metal content, reddening, and true distance modulus of RR Lyrae stars (RRLs). The method is based on homogeneous optical (BVI) and near-infrared (JHK) mean magnitudes and on predicted period–luminosity–metallicity relations (IJHK) and absolute mean magnitude–metallicity relations (BV)

Stellar rotation, parameterized by a star's projected rotational velocity v sin i, is a fundamental parameter linked to star formation, evolution, and dynamical interaction.These are still poorly understood for OB stars, which typically rotate faster than their lower-mass counterparts. We determine v sin i for 210 field OB stars in the Small

We present the discovery of a small kinematically decoupled core of 0.″2 (60 pc) in radius as well as an outflow jet in the archetypical AGN-starburst "composite" galaxy NGC 7130 from integral field data obtained with the adaptive optics-assisted MUSE-NFM instrument on the VLT. Correcting the already good natural seeing at the time of our science

We report the development of a four-color simultaneous camera for the 1.52-m Telescopio Carlos Sánchez in the Teide Observatory, Canaries, Spain. The instrument, named MuSCAT2, has a capability of four-color simultaneous imaging in g (400 to 550 nm), r (550 to 700 nm), i (700 to 820 nm), and zs (820 to 920 nm) bands. MuSCAT2 equips four 1024 × 1024