Disks around Young O-B (Proto)Stars: Observations and Theory

TL;DR

This paper reviews current knowledge on accretion disks around young high-mass stars, discussing their properties, stability, and implications for star formation, highlighting differences between stars below and above 20 solar masses.

Contribution

It provides a comprehensive review of observational and theoretical insights into disks around high-mass (proto)stars, emphasizing the scarcity of stable disks in stars above 20 solar masses.

Findings

Disks are common around stars less than 20 solar masses.

No clear examples of stable disks around proto O4-O8 stars.

Disks in 10-20 solar mass stars are likely unstable with short lifetimes.

Abstract

Disks are a natural outcome of the star formation process in which they play a crucial role. Luminous, massive stars of spectral type earlier than B4 are likely to be those that benefit most from the existence of accretion disks, which may significantly reduce the effect of radiation pressure on the accreting material. The scope of the present contribution is to review the current knowledge about disks in young high-mass (proto)stars and discuss their implications. The issues of disk stability and lifetime are also discussed. We conclude that for protostars of less than ~20 solar masses, disks with mass comparable to that of the central star are common. Above this limit the situation is unclear and there are no good examples of proto O4-O8 stars surrounded by accretion disks: in these objects only huge, massive, toroidal, non-equilibrium rotating structures are seen. It is clear on the other hand that the observed disks in stars of 10-20 solar masses are likely to be unstable and with short lifetimes.