Stars with an external convective envelope have rotation periods that evolve as the square root of the age on the main sequence. This led to empirical "gyrochronology" relations, which should allow us to determine the age of a star from its surface rotation period. Recently, the exquisite Kepler data showed that there is a stalling of the magnetic

Besides the standard analysis based on mean properties, Surface Brightness Fluctuations (SBF) spectra provide an alternative way for studying stellar populations in galaxies. Metal-poor populations are predicted in galaxy formation models, but so far remain undetected beyond the Local Group. The SBF spectra have the potential to unveil these metal

We investigate the physical nature and origin of the gamma-ray emission from the extended source HESS J1841-055 observed at TeV and GeV energies. We observed HESS J1841-055 at TeV energies for a total effective time of 43 h with the MAGIC telescopes, in 2012 and 2013. Additionally, we analysed the GeV counterpart making use of about 10 yr of Fermi

Planetary Nebulae (PNe) are the descendants of low- and intermediate-mass stars (0.8--8.0 M☉). The shape of the PN takes place at some point between the asymptotic giant branch (AGB) and the white dwarf (WD) stellar phases. Among the astrophysical phenomena, the PNe shows an impressive variety of complex morphologies. In fact, most of the PNe known

In this work, we study the structure of the outer Galactic disk up to Galactocentric distance R=20 kpc. We use the Gaia DR2 data on which we apply a deconvolution technique in the parallax errors. We recover for each line of sight the distribution of stars as a function of distance, which we use to construct density maps, that we analyze. We study

Chemically tagging groups of stars born in the same birth cluster is a major goal of spectroscopic surveys. To investigate the feasibility of such strong chemical tagging, we perform a blind chemical tagging experiment on abundances measured from APOGEE survey spectra. We apply a density-based clustering algorithm to the 8D chemical space defined