Discovery of dusty sub-solar mass young stellar objects in NGC 346 with JWST/NIRCam

TL;DR

This study utilizes JWST/NIRCam to identify and analyze a large population of sub-solar mass young stellar objects in NGC 346, revealing embedded low-mass star formation and dust presence at low metallicity in an extragalactic environment.

Contribution

First detection of embedded low-mass star formation in an extragalactic environment using JWST/NIRCam, demonstrating its superior sensitivity and resolution.

Findings

Detected ~500 YSOs and PMS stars in NGC 346.

JWST/NIRCam reaches over 10 magnitudes deeper than Spitzer.

Evidence of dust and accretion at low metallicity.

Abstract

JWST observations of NGC 346, a star-forming region in the metal-poor Small Magellanic Cloud, reveal a substantial population of sub-solar mass young stellar objects (YSOs) with IR excess. We detected $\sim$500 YSOs and pre main sequence (PMS) stars from more than 45,000 unique sources utilizing all four NIRCam wide filters with deep, high-resolution imaging, where ongoing low-mass star formation is concentrated along dust filaments. From these observations, we construct detailed near-IR colour-magnitude diagrams with which preliminary categorizations of YSO classes are made. For the youngest, most deeply-embedded objects, JWST/NIRCam reaches over 10 magnitudes below Spitzer observations at comparable wavelengths, and two magnitudes fainter than HST for more-evolved PMS sources, corresponding to $\sim$0.1 M$_\odot$. For the first time in an extragalactic environment, we detect embedded low-mass star-formation. Furthermore, evidence of IR excess and accretion suggests that dust required for rocky planet formation is present at metallicities as low as 0.2 $Z_\odot$.