Scorpius-Centaurus is the nearest OB association and its hundreds of members were divided into sub-groups , including Lower Centaurus Crux .
Here we study the dynamics of the Lower Centaurus Crux area .
We report the revelation of a large moving group containing more than 1800 intermediate- and low-mass young stellar objects and brown dwarfs , that escaped identification until Gaia DR2 allowed to perform a kinematic and photometric selection .
We investigate the stellar and substellar content of this moving group using the Gaia DR2 astrometric and photometric measurements .
The median distance of the members is 114.5 pc and 80 % lie between 102 and 135 pc from the Sun .
Our new members cover a mass range of 5 M _ { \odot } to 0.02 M _ { \odot } , and add up to a total mass of about 700 M _ { \odot } .
The present-day mass function follows a log-normal law with m _ { c } = 0.22 M _ { \odot } and \sigma = 0.64 .
We find more than 200 brown dwarfs in our sample .
The star formation rate had its maximum of 8 \times 10 ^ { -5 } M _ { \odot } yr ^ { -1 } at about 9 Myr ago , We grouped the new members in four denser subgroups , which have increasing age from 7 to 10 Myr , surrounded by “ free-floating ” young stars with mixed ages .
Our isochronal ages , now based on accurate parallaxes , are compatible with several earlier studies of the region .
The whole complex is presently expanding , and the expansion started between 8 to 10 Myr ago .
Two hundred members show infrared excess compatible with circumstellar disks from full to debris disks .
This discovery provides a large sample of nearby young stellar and sub-stellar objects for disk and exoplanet studies .