Low-Metallicity Star Formation Survey in Sh2-284 (LZ-STAR): The Core Mass Function

arXiv:2607.25753 · astro-ph.GA, astro-ph.SR · Submitted 2026-07-28 · Read on arXiv

astro-ph.GA, astro-ph.SR

Submitted: 2026-07-28

Updated: 2026-09-22

Comments: 14 pages, 4 figures, submitted to ApJ, comments welcome

License: http://creativecommons.org/licenses/by/4.0/

The gist: We present an ALMA 1.3 mm dust continuum study of the dense core mass function (CMF) in Sh2-284, a low metallicity outer Galaxy star-forming complex with Z about1/3 -- 1/2 Z.

Terminology

Abstract

We present an ALMA 1.3 mm dust continuum study of the dense core mass function (CMF) in Sh2-284, a low metallicity outer Galaxy star-forming complex with Z about1/3 -- 1/2 Z. The observations cover six far-infrared bright subregions at about 0.65" (3000 au) resolution. We identify a total of 91 candidate dense cores and define a robust catalog of 68 cores with Gaussian fitting. The high-mass CMF above 2.5 Msun is well described by a Salpeter-like slope, with a fiducial forward-modeled value of alpha=1.22+0.24-0.22 for dN/d M proportional to M-alpha. Together with existing constraints on the initial mass function (IMF) of Sh2-284, the Salpeter-like CMF is consistent with a resemblance between the CMF and IMF shapes in the outer Galaxy environments, suggesting that moderately low metallicity alone does not strongly reshape the high-mass CMF/IMF slope.

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