A FLAMINGOS Deep Near Infrared Imaging Survey of the Rosette Complex I: Identification and Distribution of the Embedded Population

TL;DR

This deep near-infrared survey of the Rosette Complex reveals the distribution and clustering of young stars, showing most formed in embedded clusters with a sequence of star formation likely driven by cloud evolution.

Contribution

The study identifies new star clusters and analyzes their properties, providing insights into the spatial distribution and evolution of star formation in the Rosette Complex.

Findings

Majority of stars are in clusters within the complex.

Infrared excess fraction increases with distance from NGC 2244.

Star formation sequence appears primordial, not HII region-driven.

Abstract

We present the results of a deep near-infrared imaging survey of the Rosette Complex. We studied the distribution of young embedded sources using a variation of the Nearest Neighbor Method applied to a carefully selected sample of near-infrared excess (NIRX) stars which trace the latest episode of star formation in the complex. Our analysis confirmed the existence of seven clusters previously detected in the molecular cloud, and identified four more clusters across the complex. We determined that 60% of the young stars in the complex and 86% of the stars within the molecular cloud are contained in clusters, implying that the majority of stars in the Rosette formed in embedded clusters. We compare the sizes, infrared excess fractions and average extinction towards individual clusters to investigate their early evolution and expansion. We found that the average infrared excess fraction of clusters increases as a function of distance from NGC 2244, implying a temporal sequence of star formation across the complex. This sequence appears to be primordial, possibly resulting from the formation and evolution of the molecular cloud and not from the interaction with the HII region.