The unexpectedly large proportion of high-mass star-forming cores in a Galactic mini-starburst

TL;DR

This study uses high-resolution ALMA observations of W43-MM1 to reveal a high-mass core mass function with a shallower slope than the stellar initial mass function, challenging existing theories of star formation.

Contribution

First to statistically characterize the high-mass core mass function in a Galactic star-forming region with unprecedented resolution.

Findings

High-mass core mass function slope is shallower than the IMF.

Reveals a large proportion of high-mass star-forming cores.

Challenges current understanding of the origin of the IMF.

Abstract

Understanding the processes that determine the stellar Initial Mass Function (IMF) is a critical unsolved problem, with profound implications for many areas of astrophysics. In molecular clouds, stars are formed in cores, gas condensations which are sufficiently dense that gravitational collapse converts a large fraction of their mass into a star or small clutch of stars. In nearby star-formation regions, the core mass function (CMF) is strikingly similar to the IMF, suggesting that the shape of the IMF may simply be inherited from the CMF. Here we present 1.3 mm observations, obtained with ALMA, the world's largest interferometer, of the active star-formation region W43-MM1, which may be more representative of the Galactic-disk regions where most stars form. The unprecedented resolution of these observations reveals, for the first time, a statistically robust CMF at high masses, with a slope that is markedly shallower than the IMF. This seriously challenges our understanding of the origin of the IMF.