Signatures of mass segregation from competitive accretion and monolithic collapse

The Astrophysical Journal The American Astronomical Society, find out more.

The Institute of Physics, find out more.

A publishing partnership

The following article isOpen access Signatures of Mass Segregation from Competitive Accretion and Monolithic Collapse Richard J. Parker1,3, Emily J. Pinson1, Hayley L. Alcock1, and James E. Dale2

Published 2024 October 1 • © 2024. The Author(s). Published by the American Astronomical Society. The Astrophysical Journal, Volume 974, Number 1 Citation Richard J. Parker et al 2024 ApJ 974 8 DOI 10.3847/1538-4357/ad6c48

DownloadArticle PDF DownloadArticle ePub Figures Tables References Download PDFDownload ePub Article metrics 41 Total downloads

Share this article Hide article and author information Author e-mails R.Parker@sheffield.ac.uk

Author affiliations 1 Department of Physics and Astronomy, The University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, UK; R.Parker@sheffield.ac.uk

2 Department of Peace and Conflict Research, Universitet Uppsala, Box 514, 751 20 Uppsala, Sweden

Author notes 3 Royal Society Dorothy Hodgkin Fellow.

ORCID iDs Richard J. Parker https://orcid.org/0000-0002-1474-7848

Dates Received 2024 March 1 Revised 2024 August 5 Accepted 2024 August 5 Published 2024 October 1 Check for updates using Crossmark

Unified Astronomy Thesaurus concepts Star forming regions; Massive stars; Star formation

Journal RSS Create or edit your corridor alerts

What are corridors?

Abstract The two main competing theories proposed to explain the formation of massive (>10 M⊙) stars—competitive accretion and monolithic core collapse—make different observable predictions for the environment of the massive stars during, and immediately after, their formation. Proponents of competitive accretion have long predicted that the most massive stars should have a different spatial distribution to lower-mass stars, through the stars being either mass segregated or being in areas of higher relative densities or sitting deeper in gravitational potential wells. We test these predictions by analyzing a suite of smoothed-particle hydrodynamics simulations where star clusters form massive stars via competitive accretion with and without feedback. We find that the most massive stars have higher relative densities, and sit in deeper potential wells, only in simulations in which feedback is not present. When feedback is included, only half of the simulations have the massive stars residing in deeper potential wells, and there are no other distinguishing signals in their spatial distributions. Intriguingly, in our simple models for monolithic core collapse, the massive stars may also end up in deeper potential wells because if massive cores fragment then the stars that form are also massive, and dominate their local environs. We find no robust diagnostic test in the spatial distributions of massive stars that can distinguish their formation mechanisms, and so other predictions for distinguishing between competitive accretion and monolithic collapse are required.