2025ApJ...990..173C


Query : 2025ApJ...990..173C

2025ApJ...990..173C - Astrophys. J., 990, 173 (2025/September-2)

LZ-STAR Survey: Low-metallicity Star Formation Survey of Sh2-284. I. Ordered Massive Star Formation in the Outer Galaxy.

CHENG Y., TAN J.C., ANDERSEN M., FEDRIANI R., ZHANG Y., ROBBERTO M., LI Z.-Y. and TANAKA K.E.I.

Abstract (from CDS):

Star formation is a fundamental, yet poorly understood, process of the Universe. It is important to study how star formation occurs in different galactic environments. Thus, here, in the first of a series of papers, we introduce the Low-metallicity Star Formation (LZ-STAR) survey of the Sh2-284 (hereafter S284) region, which, at Z ∼ 0.3-0.5Z⊙, is one of the lowest-metallicity star-forming regions of our Galaxy. LZ-STAR is a multifacility survey, including observations with JWST, the Atacama Large Millimeter/submillimeter Array (ALMA), Hubble Space Telescope, Chandra, and Gemini. As a starting point, we report JWST and ALMA observations of one of the most massive protostars in the region, S284p1. The observations of shock-excited molecular hydrogen reveal a symmetric, bipolar outflow originating from the protostar, spanning several parsecs, and fully covered by the JWST field of view and ALMA observations of CO(2-1) emission. These allow us to infer that the protostar has maintained a relatively stable orientation of disk accretion over its formation history. The JWST near-infrared continuum observations detect a centrally illuminated bipolar outflow cavity around the protostar, as well as a surrounding cluster of low-mass young stars. We develop new radiative transfer models of massive protostars designed for the low metallicity of S284. Fitting these models to the protostar's spectral energy distribution implies a current protostellar mass of ∼10 M⊙ has formed from an initial ∼100 M⊙ core over the last ∼3 × 105 yr. Overall, these results indicate that massive stars can form in an ordered manner in low-metallicity, protocluster environments.

Abstract Copyright: © 2025. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Jets - Star formation - Metallicity - Young stellar objects - Massive stars

Simbad objects: 7

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Number of rows : 7
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026
#notes
1 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 12317 1
2 NGC 346 Cl* 00 59 04.4000 -72 10 39.000           ~ 547 0
3 NAME Edge Cloud 2 MoC 02 48.5 +58 28           ~ 30 1
4 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 19090 0
5 HH 1177 HH 05 49 02.3 -70 05 25           ~ 6 0
6 Cl Dolidze 25 OpC 06 45 06 +00 18.0   8.19 7.6     ~ 79 1
7 LBN 211.65-01.51 HII 06 45 28 +00 17.8           ~ 75 0

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