English

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

Astrophysics of Galaxies 2026-07-28 v1 Solar and Stellar Astrophysics

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 Z1/3Z\sim1/3--1/2 Z1/2~Z_\odot. The observations cover six far-infrared bright subregions at \sim0.65" (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 α=1.220.22+0.24\alpha=1.22^{+0.24}_{-0.22} for dN/dlogMMαdN/d\log M\propto 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.

Keywords

Cite

@article{arxiv.2607.25753,
  title  = {Low-Metallicity Star Formation Survey in Sh2-284 (LZ-STAR): The Core Mass Function},
  author = {Yu Cheng and Jonathan C. Tan and Morten Andersen and Alva Kinman and Rubén Fedriani and Kei E. I. Tanaka and Yichen Zhang},
  journal= {arXiv preprint arXiv:2607.25753},
  year   = {2026}
}

Comments

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