# Evidence for Different Disk Mass Distributions Between Early and Late-Type Be Stars in the BeSOS Survey

## TL;DR

This study analyzes the disk mass and angular momentum distributions of Be stars, revealing significant differences between early and late spectral types and comparing observed data with stellar evolution models.

## Contribution

It provides the first detailed comparison of disk mass distributions between early and late-type Be stars using a large sample from the BeSOS survey.

## Key findings

- Disk masses are larger in early-type Be stars.
- Disk angular momentum differs significantly between spectral types.
- Observed disk masses exceed theoretical predictions.

## Abstract

The circumstellar disk density distributions for a sample of 63 Be southern stars from the BeSOS survey were found by modelling their H$\alpha$ emission line profiles. These disk densities were used to compute disk masses and disk angular momenta for the sample. Average values for the disk mass are 3.4$\times$10$^{-9}$ and 9.5$\times$10$^{-10}$ $M_{\star}$ for early (B0-B3) and late (B4-B9) spectral types, respectively. We also find that the range of disk angular momentum relative to the star are between 150-200 and 100-150 $J_{\star}/M_{\star}$, again for early and late-type Be stars respectively. The distributions of the disk mass and disk angular momentum are different between early and late-type Be stars at a 1\% level of significance. Finally, we construct the disk mass distribution for the BeSOS sample as a function of spectral type and compare it to the predictions of stellar evolutionary models with rapid rotation. The observed disk masses are typically larger than the theoretical predictions, although the observed spread in disk masses is typically large.