On the Spatial Distribution of Luminous Blue Variables, B[e] Supergiants, and Wolf-Rayet stars in the Large Magellanic Cloud

TL;DR

This study analyzes the spatial distributions of luminous blue variables, B[e] supergiants, and Wolf-Rayet stars in the Large Magellanic Cloud to understand their evolutionary relationships and ages, revealing diverse population dispersions and correlations.

Contribution

It provides a comprehensive spatial analysis using a new reference catalog, clarifying the evolutionary status and relationships of massive stars in the LMC with improved statistical methods.

Findings

LBVs are generally not isolated and share spatial distributions with similar stars.

B[e] supergiants are more dispersed and older than LBVs.

Certain WN and WC stars are associated with evolved supergiants, supporting evolutionary links.

Abstract

We examine the spatial distributions of LBVs, B[e] supergiants, and W-R stars in the LMC, to clarify their relative ages, evolutionary states, and relationships. This survey employs a reference catalog that was not available for previous work, comprising more than 3900 of the LMC's most luminous stars. Our analysis shows that LBVs, B[e] supergiants, and WR's have spatial distributions like normal stars with the same spectral types and luminosities. Most LBVs are not isolated, nor do they require binary or multiple status to explain their spatial relationship to other populations. There are two likely exceptions: one lower-luminosity LBV and one LBV candidate are relatively isolated and may have velocities that require additional acceleration. The B[e] supergiants are spatially and kinematically more dispersed than LBVs, suggesting that they belong to an older population. The most luminous early-type WN's are most closely associated with the evolved late O-type supergiants. The high luminosity late WNs, and WNh stars however, are highly concentrated in the 30 Dor region which biases the analysis. The less luminous WNs and WCs are associated with a mix of evolved late B, A-type, and yellow supergiants which may be in a post-red-supergiant phase. Spatial distributions of the less luminous WN, WC, and WN3/O3 stars reinforce proposed evolutionary links among those subtypes. Our analysis also demonstrates the importance of using a comprehensive census, with reference populations clearly defined by spectral type and luminosity, and how small number statistics, especially combined with spatial clustering, can invalidate some commonly-cited statistical tests.