Formation of large circumstellar discs in multiscale, ideal-MHD simulations of magnetically critical, massive pre-stellar cores
Year: 2025
Type: article
Abstract: ABSTRACT The formation of circumstellar discs is a critical step in the formation of stars and planets. Magnetic fields can strongly affect the evolution of angular momentum during prestellar core collapse, potentially leading to the failure of protostellar disc formation. This phenomenon, known as the magnetic braking catastrophe, has been observed in ideal-magentohydrodynamics (MHD) simulations. In this work, we present results from ideal-MHD simulations of circumstellar disc formation from realistic initial conditions of strongly magnetized, massive cores with masses between $30$ and $300 ~{\rm M}_\odot$ resolved by zooming into giant molecular clouds (GMCs) with masses $\sim 10^4 \ {\rm M}_\odot$ and initial mass-to-flux ratios $0.6 \le \mu _0 \le 3$. Due to the large turbulence in the gas, the dominant vertical support of discs is turbulent motion, while magnetic and turbulent pressures contribute equally in the outer toroid. We find that large Keplerian discs can form even in magnetically critical or near-critical cores due to the suppression of magnetic braking by highly turbulent and incoherent magnetic field topologies. Only cores in GMCs with $\mu _0 < 1$ fail to form discs. Instead, they collapse into a sheet-like structure and produce numerous low-mass stars. We also discuss a universal $B{\small --}\rho$ relation valid over a large range of scales from the GMC to massive cores, irrespective of the GMC magnetization. This study differs from the vast literature on this topic which typically focus on smaller mass discs with idealized initial and boundary conditions, therefore providing insights into the initial conditions of massive prestellar core collapse and disc formation.
Authors: Chong-Chong He, Massimo Ricotti
Institution: University of Maryland, College Park
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,046
Awards: G6327983680, A KEY GOAL OF COSMOLOGY IS TO UNDERSTAND THE ORIGIN AND EVOLUTION OF NONLINEAR STRUCTURE IN THE UNIVERSE INCLUDING STARS GALAXIES AND BLACK HOLES. RICH NEW SETS OF DATA WILL BECOME AVAILABLE SOON FROM MISSIONS SUCH AS JWST WFIRST X-RAY SURVEYOR ATHENA AND LISA AND WILL ADD TO OUR BREADTH OF INFORMATION ABOUT THIS CRITICAL EPOCH. ALTHOUGH CONSIDERABLE EFFORT HAS BEEN DEVOTED TO LARGE-SCALE COSMOLOGICAL SIMULATIONS WITH THE GOAL OF PROVIDING THEORETICAL GUIDANCE FOR THESE UPCOMING MISSIONS LESS ATTENTION HAS BEEN PAID TO THE EQUALLY IMPORTANT SMALLER-SCALE ASTROPHYSICAL PROCESSES THAT UNDERLIE THESE SIMULATIONS AND ARE BELOW THE RESOLUTION LIMIT OF MOST COSMOLOGICAL SIMULATIONS. WE PROPOSE TO EXPLORE SEVERAL ASPECTS OF THIS UNDERLYING ASTROPHYSICS RELATED TO COMPACT STAR CLUSTERS AT HIGH REDSHIFTS INCLUDING (1) THEIR ROLE IN THE PRODUCTION OF SEEDS FOR SUPERMASSIVE BLACK HOLES (SMBHS) (2) THE PHYSICS OF THEIR FORMATION AND GROWTH INCLUDING SUPER-EDDINGTON ACCRETION AND CLOUD FRAGMENTATION (3) THE ROLE OF X-RAY HEATING ON TRIGGERING COMPACT CLUSTERS FORMATION AND (4) THEIR EFFECT ON THE REIONIZATION OF THE UNIVERSE. WE WILL LINK OUR FINDINGS TO PREDICTION AND INTERPRETATION OF DATA FROM MISSIONS SUCH AS THOSE LISTED ABOVE. THIS WORK HAS DIRECT RELEVANCE TO STRATEGIC OBJECTIVE 1.6 OF NASA: DISCOVER HOW THE UNIVERSE WORKS EXPLORE HOW IT BEGAN AND EVOLVED AND SEARCH FOR LIFE ON PLANETS AROUND OTHER STARS. WITHIN THIS OBJECTIVE WE WILL INVESTIGATE THE NATURE OF BLACK HOLES AND THE PROCESSES OF FORMATION OF STARS AND GALAXIES.
OpenAlex ID: W4410217676