The accretion history of high-mass stars: An ArT\'eMiS pilot study of Infrared Dark Clouds

TL;DR

This study uses 350-micron continuum mapping of infrared dark clouds to investigate whether high-mass stars primarily grow from dense cores or through the dynamical evolution of larger clumps, favoring the latter scenario.

Contribution

It provides observational evidence supporting the clump-fed accretion model for high-mass star formation using new continuum maps and evolutionary track comparisons.

Findings

Clump-fed accretion models better match observed data.

Identified ~200 compact sources in IRDCs.

Supports dynamical evolution of parsec-scale clumps as key to high-mass star growth.

Abstract

The mass growth of protostars is a central element to the determination of fundamental stellar population properties such as the initial mass function. Constraining the accretion history of individual protostars is therefore an important aspect of star formation research. The goal of the study presented here is to determine whether high-mass (proto)stars gain their mass from a compact (<0.1pc) fixed-mass reservoir of gas, often referred to as dense cores, in which they are embedded, or whether the mass growth of high-mass stars is governed by the dynamical evolution of the parsec-scale clump that typically surrounds them. To achieve this goal, we performed a 350micron continuum mapping of 11 infrared dark clouds, along side some of their neighbouring clumps, with the ArT\'eMiS camera on APEX. By identifying about 200 compact ArT\'eMiS sources, and matching them with Herschel Hi-GAL 70micron sources, we have been able to produce mass vs. temperature diagrams. We compare the nature (i.e. starless or protostellar) and location of the ArT\'eMiS sources in these diagrams with modelled evolutionary tracks of both core-fed and clump-fed accretion scenarios. We argue that the latter provide a better agreement with the observed distribution of high-mass star-forming cores. However, a robust and definitive conclusion on the question of the accretion history of high-mass stars requires larger number statistics.