Absence of High-mass Prestellar Cores in the Orion Giant Molecular Cloud

TL;DR

This study used ALMA observations to search for high-mass prestellar cores in Orion GMC but found none exceeding 11 solar masses, supporting previous findings that such cores are rare or absent.

Contribution

First targeted search for high-mass prestellar cores in Orion GMC using ALMA, providing new observational constraints on their existence.

Findings

No high-mass prestellar cores found above 11 Msun in Orion

Results align with previous surveys indicating scarcity of such cores

Challenges the core-fed model of high-mass star formation in Orion

Abstract

A fundamental difference between "core-fed" and "clump-fed" star formation theories lies in the existence or absence of high-mass cores at the prestellar stage. However, only a handful of such cores have been observed. Here, different than previous search in distributed star formation regions in the Galactic plane, we search for high-mass prestellar cores in the Orion GMC, by observing the 7 most massive starless cores selected from previous deep continuum surveys. We present ALMA ACA Band 6 and Band 7 continuum and line observations toward the 7 cores, in which we identify 9 dense cores at both bands. The derived maximum core mass is less than 11 Msun, based on different dust temperatures. We find no high-mass prestellar cores in this sample, aligning with the results of previous surveys, thereby challenging the existence of such cores in Orion. Outside Orion, further detailed studies are needed for remaining high-mass prestellar core candidates to confirm their status as massive, starless cores.