The young \sigma Orionis cluster in the Orion Belt is an incomparable site for studying the formation and evolution of high-mass , solar-like , and low-mass stars , brown dwarfs , and substellar objects below the deuterium burning mass limit .
The first version of the Mayrit catalogue was a thorough data compilation of cluster members and candidates , which is regularly used by many authors of different disciplines .
I show two new applications of the catalogue and advance preliminar results on very wide binarity and the initial mass function from 18 to 0.035 M _ { \odot } in \sigma Orionis .
The making-up of a new version of the Mayrit catalogue with additional useful data is in progress .