Magnetic fields and radiative feedback in the star formation process

TL;DR

This paper reviews recent advances in understanding star formation by incorporating magnetic fields and radiative feedback into numerical simulations, highlighting their roles in star formation efficiency and related challenges.

Contribution

It presents new self-gravitating radiation-magnetohydrodynamics simulations of star cluster formation, integrating magnetic fields and radiative transfer into SPH methods.

Findings

Magnetic fields and radiative heating help explain slow, inefficient star formation.

Magnetic fields pose challenges for protostellar disc and binary star formation.

Inclusion of physics improves understanding but reveals unresolved issues.

Abstract

Star formation is a complex process involving the interplay of many physical effects, including gravity, turbulent gas dynamics, magnetic fields and radiation. Our understanding of the process has improved substantially in recent years, primarily as a result of our increased ability to incorporate the relevant physics in numerical calculations of the star formation process. In this contribution we present an overview of our recent studies of star cluster formation in turbulent, magnetised clouds using self-gravitating radiation-magnetohydrodynamics calculations (Price and Bate 2008, 2009). Our incorporation of magnetic fields and radiative transfer into the Smoothed Particle Hydrodynamics method are discussed. We highlight how magnetic fields and radiative heating of the gas around newborn stars can solve several of the key puzzles in star formation, including an explanation for why star formation is such a slow and inefficient process. However, the presence of magnetic fields at observed strengths in collapsing protostellar cores also leads to problems on smaller scales, including a difficulty in forming protostellar discs and binary stars (Price and Bate 2007, Hennebelle and Teyssier 2008), which suggests that our understanding of the role of magnetic fields in star formation is not yet complete.