SIMBAD references

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 μm, but is extremely faint at 7.7 μm and entirely undetected at shorter wavelengths. MZS-1 exhibits an elliptical morphology with a major axis of approximately 8″ and a minor axis of about 4″. 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. Spectral energy distribution fitting using the T. P. Robitaille () model grids identifies these sources as Stage I young stellar objects (YSOs) with masses below ∼3 M_⊙ and total stellar mass of the protocluster ≈∼300 M_⊙ (based on 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.