The Chandra Carina Complex Project View of Trumpler 16

TL;DR

This study uses new and archival X-ray data to analyze the structure, stellar population, and properties of Trumpler 16, revealing its sub-clustering, stellar content, and disk frequency, and comparing it to other clusters like Orion.

Contribution

It provides a detailed X-ray based analysis of Trumpler 16, including a revised source list, population estimate, and insights into its structure and stellar properties, which were not previously available.

Findings

1232 X-ray sources identified, with 1187 likely cluster members.

Estimated total pre-main sequence population exceeds 6500 stars.

Detected X-ray emission from 29 high-mass stars, spectral types B2 to O3.

Abstract

Trumpler 16 is a well--known rich star cluster containing the eruptive supergiant $\eta$ Carin\ae\ and located in the Carina star-forming complex. In the context of the Chandra Carina Complex Project, we study Trumpler 16 using new and archival X-ray data. A revised X-ray source list of the Trumpler 16 region contains 1232 X-ray sources including 1187 likely Carina members. These are matched to 1047 near-infrared counterparts detected by the HAWK-I instrument at the VLT allowing for better selection of cluster members. The cluster is irregular in shape. Although it is roughly circular, there is a high degree of sub-clustering, no noticeable central concentration and an extension to the southeast. The high--mass stars show neither evidence of mass segregation nor evidence of strong differential extinction. The derived power-law slope of the X-ray luminosity function for Trumpler 16 reveals a much steeper function than the Orion Nebula Cluster implying different ratio of solar- to higher-mass stars. We estimate the total Trumpler 16 pre-main sequence population to be > 6500 Class II and Class III X-ray sources. An overall K-excess disk frequency of ~ 8.9% is derived using the X-ray selected sample, although there is some variation among the sub-clusters, especially in the Southeastern extension. X-ray emission is detected from 29 high--mass stars with spectral types between B2 and O3.