Young Stellar Objects in NGC 346: A JWST NIRCam/MIRI Imaging Survey

TL;DR

This JWST survey of NGC 346 in the SMC identified over 200,000 sources, including 196 YSOs, expanding knowledge of extragalactic star formation and detecting the lowest-mass YSOs outside our galaxy.

Contribution

First JWST imaging survey of NGC 346 combining NIRCam and MIRI data, identifying and classifying YSOs, including the lowest-mass extragalactic YSOs confirmed.

Findings

Detected over 200,000 sources in NGC 346.

Identified 196 YSOs and 833 YSO candidates.

Confirmed YSOs approaching 1 solar mass.

Abstract

We present a JWST imaging survey with NIRCam and MIRI of NGC 346, the brightest star-forming region in the Small Magellanic Cloud (SMC). By combining aperture and point spread function (PSF) photometry of eleven wavelength bands across these two instruments, we have detected more than 200,000 unique sources. Using near-infrared (IR) color analysis, we observe various evolved and young populations, including 196 young stellar objects (YSOs) and pre-main sequence stars suitable for forthcoming spectroscopic studies. We expand upon this work, creating mid-IR color-magnitude diagrams and determining color cuts to identify 833 reddened sources which are YSO candidates. We observe that these candidate sources are spatially associated with regions of dusty, filamentary nebulosity. Furthermore, we fit model YSO spectral energy distributions (SEDs) to a selection of sources with detections across all of our MIRI bands. We classify with a high degree of confidence 23 YSOs in this sample and estimate their radii, bolometric temperatures, luminosities, and masses. We detect YSOs approaching 1 solar mass, the lowest-mass extragalactic YSOs confirmed to date.