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arXiv · 2509.09617

Detection of a Deeply Embedded Protocluster Candidate in NGC 602 with JWST

Beena Meena·Peter Zeidler·Elena Sabbi·Antonella Nota·Camilla Pacifici·Olivia C. Jones
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Abstract

JWST NIRCam and MIRI photometry of NGC 602, a low-metallicity young star cluster in the Small Magellanic Cloud, reveals an extended mid-infrared bright emission feature designated as MZS-1. This feature is prominent between 10 and 25.5 microns, but is extremely faint at 7.7 microns and entirely undetected at shorter wavelengths. MZS-1 exhibits an elliptical morphology with a major axis of approximately 8 arcseconds and a minor axis of about 4 arcseconds. Its elongated shape and multiple emission peaks in the two-dimensional flux map suggest a group of deeply embedded sources with blackbody-like temperatures ranging from 100 K to 140 K. SED fitting using the Robitaille 2017 model grids identifies these sources as Stage I young stellar objects (YSOs) with masses below approximately 3 solar masses and a total stellar mass of the protocluster of about 300 solar masses (based on a Salpeter IMF). The low YSO masses are consistent with their absence in Spitzer-based catalogs due to sensitivity limits. By revealing a deeply embedded, low-mass protocluster invisible in previous surveys, this work highlights JWST's unparalleled resolution and sensitivity in uncovering the earliest stages of low-mass cluster formation in the metal-poor regime.

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Beena Meena, Peter Zeidler, Elena Sabbi, Antonella Nota, Camilla Pacifici, Olivia C. Jones. 2025-09-11. Detection of a Deeply Embedded Protocluster Candidate in NGC 602 with JWST. https://arxiv.org/abs/2509.09617

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