2025-05-26 –, Main Conference Room
Precise large-scale astrometric data have provided a fresh perspective of star forming regions, which encode key information on cloud formation processes and stellar evolution. We can now resolve their non-trivial star formation histories in great detail for the first time. The well-studied Orion star forming region is a prime example of the complexity associated with the star forming process. However, despite its importance, a comprehensive mapping and characterization of its stellar populations, including the embedded Young Stellar Objects (YSOs), is still lacking.
In my talk, I will present a homogeneous, holistic spatio-kinematic analysis of the Orion region based on Gaia mDR3 data. Leveraging the Significance Mode Analysis (SigMA) clustering algorithm, specifically tailored to 5D positional and kinematic phase-space data, I aim to contribute to a deeper understanding of Orion’s complex structure and evolution. We find that the region separates into ~40 co-spatial and co-moving stellar groups (> 15,000 stars). Compared to other works, we validate most previously found groups, but often reach 50-100% richer member counts, and also discover ~8 new groups. Estimating the age of each group, we discuss possible coherent age-position patterns, as were found for the Sco-Cen OB association.
Orion also comprises active star forming sites with extended nebulosity, such as the Flame Nebula. The YSOs embedded there are excellent gas motion tracers, but are mainly visible in the Infrared. Using ESO data from three surveys, we successfully calculate proper motions on the order of 1 mas/yr for the YSOs at ~400 pc and perform a kinematic analysis for the Flame Nebula.
I will conclude with a high-resolution star formation history of Orion, revealing a rich tapestry of sub-populations with distinct kinematics and ages. I will also summarize and discuss the motion trends we find for different YSO classes in the Flame Nebula and their implications on the evolution of the cluster.
