The analysis of a long X-ray observation reveals the nature of the mysterious star Wd1-9: a binary system containing a star that has recently evolved into the Wolf-Rayet phase, after expelling the outer layers of its atmosphere, which were accreted onto the companion star. Among the at least one hundred billion stars hosted by our Galaxy, there are a
The amount of gas that is converted into stars by the star formation process is described by the star formation rate. For instance, in the Milky Way today between 0.7 and 1.5 solar masses of gas are converted into stars each year. However, this a mean value across our Galaxy, since locally clouds can start forming stars at higher rates
