Stars born in filaments tend to outweigh stars formed in the field
The mass distribution of stars is called the initial mass function, or IMF for short, and it characterizes the properties not only of our Milky Way, but of all the other galaxies we observe as well. But is the IMF constant? Does it vary from galaxy to galaxy? Does it vary within our galaxy? After decades of studying we still are not sure how the environment affects the process of star formation, aside from the fact that the IMF seems peculiarly constant within the Milky Way.
Ironically this failure in our understanding is mainly due to the fact that stars are very private individuals that hide their forming years behind very cold and dusty environments, which we can only probe using long wavelength observations such as those in the infrared. The Herschel mission, however, has recently opened for us a window in the star formation environments with spectacular results.