Exploring the stellar populations and the star formation history of the Carina OB1 association

Göppl, Christiane (2026): Exploring the stellar populations and the star formation history of the Carina OB1 association. Dissertation, LMU München: Fakultät für Physik

Abstract

Most stars are born as part of star clusters and associations. A characterization of these regions is therefore crucial to learn more about the environments in which stars form. In particular, knowledge about the exact positions of high-mass stars is of importance as these stars exert a strong influence on the evolution and formation of low-mass stars, protostellar disks, and exoplanets. One prominent region where star formation is still ongoing is the Carina OB1 association. In this thesis, I will provide a detailed characterization of the Car OB1 association over its full spatial extent of 5°x5°, including its clusters and high-mass star population, and propose a formation scenario for the association. We first carry out an unbiased search for stellar clusters and groups within the whole association by applying a clustering algorithm to the astrometric data of stars from the Gaia DR3 survey. We then classify the clusters and groups as members of the association if their distance and age are compatible with Car OB1, and find in total 15 stellar clusters and groups that fulfill the criteria. To quantify the size of clustered and distributed high-mass populations, we first compile a sample of spectroscopically confirmed high-mass stars and then complement the sample by searching for high-mass star candidates. For this, we combine the astrometric data with the stellar astrophysical parameters table from Gaia DR3 and select all stars with compatible distances in the Car OB1 region, which results in the so far largest catalog of high-mass stars in Car OB1 with 770 OB stars and 604 new OB star candidates. As 74% of the high-mass are part of the distributed population, this fraction is a significant increase from previously determined values of ~50%. With accurate cluster positions, distances, and motions available, we can now construct the first star formation scenario for the entire association. We trace back the positions of the clusters over the last 13 Myr and calculate how many supernovae have already occurred based on the older clusters' IMF extrapolation. Our analysis suggests that the oldest cluster of the association, NGC 3293, was formed in the Sagittarius-Carina spiral arm and that its surrounding superbubble led to the formation of other massive clusters, Trumpler 14, 15, and 16.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Themengebiete: 500 Naturwissenschaften und Mathematik ; 500 Naturwissenschaften und Mathematik > 530 Physik
• Fakultäten: Fakultät für Physik
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 25. Februar 2026
• 1. Bericht­erstatter:in: Preibisch, Thomas