Massive stars, those over ten times heavier than our Sun, are the conduits of most elements of the periodic table and drive the morphological and chemical makeup of their host galaxies. Yet the origin of the most luminous and hottest stars among them, called 'blue supergiants', has been debated for many decades. Blue supergiants are strange stars. First, they are observed in large numbers, despite conventional stellar physics expecting them to live only briefly. Second, they are typically found alone, despite most massive stars being born with companions. Third, the majority of them harbour

The universality of the stellar initial mass function (IMF) is one of the most widespread assumptions in modern Astronomy and yet, it might be flawed. While observations in the Milky Way generally support an IMF that is invariant with respect to the local conditions under which stars form, measurements of massive early-type galaxies systematically point towards a non-universal IMF. To bridge the gap between both sets of evidence, in this work we measured for the first time the low-mass end of the IMF from the integrated spectra of a Milky Way-like galaxy, NGC3351. We found that the slope of

The properties of blue supergiants are key for constraining the end of the main sequence phase, a phase during which massive stars spend most of their lifetimes. The lack of fast-rotating stars below 21.000K, a temperature around which stellar winds change in behaviour, has been proposed to be caused by enhanced mass-loss rates, which would spin down the star. Alternatively, the lack of fast-rotating stars may be the result of stars reaching the end of the main sequence. Here, we combine newly derived estimates of photospheric and wind parameters, wind terminal velocities from the literature