A pan-European study revealed details of star counts and their space motions within the spatially-close Lupus starforming region, using largely GAIA data. They identified 137 high-probability members of the Lupus association of young stars, including 47 stars that had never been reported as members before. Many of the historically known stars associated with the Lupus region are more likely to be field stars or members of the adjacent Scorpius-Centaurus association. Their new sample of members covers the magnitude and mass range from about 8-18 Gmag and from 0.03 to 2.4 M☉, respectively.
The Lupus association appears to be younger (at 1-6 Myr) than the population of young stars in the Corona Australis star-forming region recently investigated by their team using a similar methodology.
The Orion Complex is a notable star forming region that is fragmented into several different populations. Marina Kounkel of Western Washington Uni has proposed a model that attempts to explain the how the Complex has evolved to its current configuration. In this model, the large scale expansion can be attributed to a supernova that exploded 6 Myr ago, the remnant of which can be seen as Barnard’s loop, as the centre of the expansion is consistent with the geometrical centre of the HII bubble. This is also similar to the ballistic expansion associated with λ Ori, a region which has also been the site of an ancient supernova. Assuming that the Orion Complex originally formed as one long filament spanning from the bottom of Orion A to ψ2 Ori (or, potentially, as far as λ Ori), Barnard’s loop supernova could have split the cloud, which led to the formation of Orion C & D. Furthermore, the shockwave that has propagated into the filament could have swept along the gas through several pc, which led to the formation of the singularly most massive cluster in the Solar Neighborhood, the ONC. She also discusses other related nearby events, such as the formation of the Monogem ring, and various runaways that have been ejected from the Orion Complex