La forma habitual de medir el tamaño de las galaxias, el radio efectivo, es el resultado de una época cuando las imágenes astronómicas eran poco profundas y, por tanto, incapaces de capturar la extensión completa de las fuentes astronómicas. Esta situación ha cambiado drásticamente en la actualidad con la llegada de cartografiados muy profundos

We use a sample of 33 H II regions with high and intermediate resolution spectroscopy to analyze the radial distribution of different elements in the Milky Way. This sample covers Galactocentric distances from 6 to 17 kpc, which have been revised using Gaia DR2 parallaxes. We calculate physical conditions and chemical abundances using updated

Accurate distances to individual Milky Way stars provided by Gaia have allowed us to derive stellar age distributions from colour─magnitude diagrams (CMD) representative of the thick disc and the local halo. The CMD for the kinematically selected halo stars showed an enigmatic double main sequence. The blue sequence had been linked to a major

The effective or half-light radius has become a very popular choice for characterising galaxy size, but it measures the concentration of light within galaxies and thus does not capture our intuitive definition of size which is related to the edge or boundary of objects. We define a new physically motivated measurement of size for galaxies, R 1

Two major features of structure in galaxy discs: the long-term presence of spiral arms, and the continuous presence of OB stars concentrated in the arms, can be explained if a spiral density wave in the stellar population interacts with star-forming gas in the disc. With a recent method we are able to perform accurate characterization of the

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