Theories of the massive star formation: a (short) review

TL;DR

This review summarizes recent numerical studies on massive star formation, focusing on overcoming radiative pressure and fragmentation issues through multi-dimensional simulations including feedback and magnetic fields.

Contribution

It highlights how combined radiative feedback and magnetic fields effectively suppress core fragmentation and facilitate the formation of stars exceeding 20 solar masses.

Findings

Multi-D simulations overcome radiative pressure barriers.

Magnetic fields reduce core fragmentation when combined with radiative feedback.

Magnetic fields focus accretion flows, increasing temperature and feedback efficiency.

Abstract

We briefly review the recent numerical works that have been performed to understand the formation of massive stars. After a brief description of the classical works, we review more specifically $i)$ the problem of building stars more massive than 20 $M_\odot$ and $ii)$ how to prevent the massive cores to fragment in many objects. Multi-D simulations succeed in circumventing the radiative pressure leading to the formation of massive stars although some questions are still debated regarding how is accretion exactly proceeding. While the core fragmentation is slightly reduced by the radiative feedback and the magnetic field when they are treated separately, it is almost entirely suppressed when both of them are included. This is because, magnetic field by removing angular momentum focusses the flow in a compact region. This makes the radiative feedback very efficient leading to a significant increase of the temperature.