Charting the Star Formation History of the Orion Complex: A Multi-Dimensional Analysis Using Gaia Data and Machine Learning

Author(s): Alena Rottensteiner, Sebastian Ratzenböck, João Alves
Abstract: Gaia's 3D view and the power of machine learning are disrupting traditional views of star formation. Instead of simple, distinct stellar populations, we now see complex regions with multiple sub-populations varying in age and motion. The Orion star-forming complex, a prominent and well-studied region, is a prime example of this complexity. Despite its importance, a comprehensive mapping and characterization of stellar populations within the Orion molecular cloud complex is still lacking.

In this contribution, I present a homogeneous, holistic spatio-kinematic analysis of the Orion region based on precise astrometric data from the third Gaia data release. Leveraging the Significance Mode Analysis (SigMA) clustering algorithm, specifically tailored to 5D positional and kinematic phase-space data accessible via Gaia, I aim to contribute to a deeper understanding of the region's complex structure and evolution.

First, I will elaborate on how we adapted SigMA to accommodate the distance of the Orion cloud complex (300-500 pc), where parallax errors begin to pose a challenge to identifying stellar groups. Following this, I will present our finding of 40 co-spatial and co-moving stellar groups (~15,000 stars), extracted from Gaia DR3 data, and compare them with established works, highlighting both consistencies and discrepancies. Generally, we validate a large portion of the previously identified groups, but oftentimes reach 50-100% richer member counts. Moreover, we find 8 previously unidentified clusters throughout the Orion complex.

Lastly, I will present estimated ages for each sub-populations identified with SigMA. This will help us analyze potential coherent age-position patterns, as we recently found in the Sco-Cen OB association, and allow for a high-resolution star formation history of the region, revealing the dominant physical processes and different stages behind the genesis of this benchmark region.. The study on Orion provides a comprehensive understanding of the star-forming complex, revealing a rich tapestry of sub-populations with distinct kinematics and ages.
Organisation(s): Department of Astrophysics, Research Group Visualization and Data Analysis, Research Network Data Science
External organisation(s): European Southern Observatory (Germany)
Publication date: 07-2024
Peer reviewed: Yes
Austrian Fields of Science 2012: 103003 Astronomy, 103004 Astrophysics
Portal url: https://ucrisportal.univie.ac.at/en/publications/12f46c10-48f2-46df-a77a-8c00279d4bba

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