Ordered Massive Star Formation in the low Metallicity Protocluster of the Milky Way

ABSTRACT :
Massive stars regulate the formation of galaxies, stars, planets and black holes across the universe. It is thus important to develop and test models of how massive stars form in a variety of galactic environments. Here we report JWST and ALMA observations of Sh2-284, one of the lowest metallicity star-forming region of our Galaxy. The JWST observations of shock-excited molecular hydrogen reveal a symmetric, bipolar outflow spanning several parsecs, indicating a stable protostellar orientation over its full formation history. The near-IR continuum images detect a centrally illuminated bipolar outflow cavity, as well as a surrounding cluster of about 200 low-mass young stars. We develop radiative transfer models of massive star formation via core accretion tailored to low-metallicity conditions and fit the protostellar spectral energy distribution from 1.6 to 500um to infer a current protostellar mass of ~10Msun, that has formed from a 60Msun core over the last 10^5 years. Overall, these results imply that massive stars can form in an ordered manner in low-metallicity, protocluster environments.