Although Le Verrier was not really interested in astrophysics, this was not the case for a number of astronomers at the Observatory. In particular, Charles Wolf (1827-1918) and Georges Rayet (1839-1906) scrutinized the sky carefully using Foucault’s 40-cm-diameter telescope, equipped with a spectroscope. They thus discovered many stars with emission spectral lines quite different from the vast majority of stars whose spectral lines are in absorption. We know today that these Wolf-Rayet stars constitute the ultimate evolutionary stage of many massive stars, before they explode as supernovae.

caption : Foucault 40 cm telescope - credits : Observatoire de Paris