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

Olivia C. Jones; Conor Nally; Nolan Habel; Laura Lenkić; Katja Fahrion; Alec S. Hirschauer; Laurie E. U. Chu; Margaret Meixner; Guido De Marchi; Omnarayani Nayak; Massimo Robberto; Elena Sabbi; Peter Zeidler; Catarina Alves de Oliveira; Tracy Beck; Katia Biazzo; Bernhard Brandl; Giovanna Giardino; Teresa Jerabkova; Charles Keyes; James Muzerolle; Nino Panagia; Klaus M. Pontoppidan; Ciaran Rogers; B. A. Sargent; David R. Soderblom

arXiv · 2301.03932

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

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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 $Z_\odot$.

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Olivia C. Jones, Conor Nally, Nolan Habel, Laura Lenkić, Katja Fahrion, Alec S. Hirschauer, Laurie E. U. Chu, Margaret Meixner, Guido De Marchi, Omnarayani Nayak, Massimo Robberto, Elena Sabbi, Peter Zeidler, Catarina Alves de Oliveira, Tracy Beck, Katia Biazzo, Bernhard Brandl, Giovanna Giardino, Teresa Jerabkova, Charles Keyes, James Muzerolle, Nino Panagia, Klaus M. Pontoppidan, Ciaran Rogers, B. A. Sargent, David R. Soderblom. 2023-01-10. Discovery of dusty sub-solar mass young stellar objects in NGC 346 with JWST/NIRCam. https://arxiv.org/abs/2301.03932

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