Abstract

Contributed Talk - Splinter MassiveStars

Monday, 09 September 2024, 16:15   (S23)

Spatial Distribution and Clustering Properties of the Young Stellar Populations in the Carina Nebula and Car OB1

Christiane Göppl, Thomas Preibisch
Universitäts-Sternwarte München, LMU

The OB association Car OB1 (which harbors the famous Carina Nebula) is one of the most massive star forming region in our galaxy and contains numerous young stellar clusters (e.g. Trumpler 14 and 16), as well as large amounts of gas and molecular clouds in which star formation is still going on today. We use Gaia DR3 astrometry and photometry to analyze the spatial distribution of the young stellar populations and stellar clusters, and to search for new OB star candidates in Car OB1. We perform a new census of high-mass stars in Car OB1 and compile a comprehensive catalog of 512 high-mass stars (including 124 O-type, WR-type, and supergiant stars) with known spectral types. We apply the clustering algorithm DBSCAN on the Gaia DR3 data of the region to find stellar clusters, determine their distances and kinematics, and estimate ages. Our DBSCAN analysis finds 15 stellar clusters and groups in Car OB1, four of which were not known before. We find evidence for expansion/contraction for five of the individual clusters at a significance $> 2sigma$. We find a global expansion of the Car OB1 association with a velocity of $v_{out} = 5.23pm0.02 km,s^{-1}$. Our kinematic traceback analysis of the high-mass stars shows that the association was in a considerably more compact configuration 3-4 Myr ago, which coincides with the age of the cluster Tr 16 in the center of the Carina Nebula. Using astrophysical parameters from Gaia DR3, we identify 15 new O-type and 621 new B-type star candidates in Car OB1. We show that a very significant fraction of (at least) 60% of the high-mass stars in Car OB1 constitute a non-clustered, distributed population of stars.