Metal-poor stars are important tools for tracing the early history of the Milky Way, and for learning about the first generations of stars. Simulations suggest that the oldest metal-poor stars are to be found in the inner Galaxy. Typical bulge surveys, however, lack low metallicity ( $\rm {[Fe/H]} \lt -1.0$ ) stars because the inner Galaxy is

We report the confirmation and mass determination of three hot Jupiters discovered by the Transiting Exoplanet Survey Satellite (TESS) mission: HIP 65Ab (TOI-129, TIC-201248411) is an ultra-short-period Jupiter orbiting a bright (V = 11.1 mag) K4-dwarf every 0.98 days. It is a massive 3.213 ± 0.078 M J planet in a grazing transit configuration with

Context. The lack of high-precision long-term continuous photometric data for large samples of stars has impeded the large-scale exploration of pulsational variability in the OB star regime. As a result, the candidates for in-depth asteroseismic modelling have remained limited to a few dozen dwarfs. The TESS nominal space mission has surveyed the

Extreme high-frequency BL Lacs (EHBL) feature their synchrotron peak of the broad-band spectral energy distribution (SED) at ν s ≥ 10 17 Hz. The BL Lac object 1ES 2344+514 was included in the EHBL family because of its impressive shift of the synchrotron peak in 1996. During the following years, the source appeared to be in a low state without

We determine the radial abundance gradient of helium in the disc of the Galaxy from published spectra of 19 H II regions and ring nebulae surrounding massive O-type stars. We revise the Galactocentric distances of the objects considering Gaia DR2 parallaxes (Gaia Collaboration 2018) and determine the physical conditions and the ionic abundance of

Context. The apparent lack of massive O-type stars near the zero-age main sequence, or ZAMS (at ages <2 Myr), is a topic that has been widely discussed in the past 40 yr. Different explanations for the elusive detection of these young massive stars have been proposed from the observational and theoretical side, but no firm conclusions have been