On the existence of accretion-driven bursts in massive star formation

TL;DR

This paper demonstrates through simulations that massive star formation involves episodic accretion events causing luminous outbursts, similar to phenomena observed in low-mass stars, suggesting a universal mechanism across star types.

Contribution

It provides the first numerical evidence that accretion-driven luminosity outbursts occur in massive star formation, extending the phenomenon beyond low-mass stars.

Findings

Massive stars experience episodic accretion and luminous outbursts.

Outbursts are caused by gaseous clumps falling onto the protostar.

Disk fragmentation may be observable through these luminous flares.

Abstract

Accretion-driven luminosity outbursts are a vivid manifestation of variable mass accretion onto protostars. They are known as the so-called FU Orionis phenomenon in the context of low-mass protostars. More recently, this process has been found in models of primordial star formation. Using numerical radiation hydrodynamics simulations, we stress that present-day forming massive stars also experience variable accretion and show that this process is accompanied by luminous outbursts induced by the episodic accretion of gaseous clumps falling from the circumstellar disk onto the protostar. Consequently, the process of accretion-induced luminous flares is also conceivable in the high-mass regime of star formation and we propose to regard this phenomenon as a general mechanism that can affect protostars regardless of their mass and/or the chemical properties of the parent environment in which they form. In addition to the commonness of accretion-driven outbursts in the star formation machinery, we conjecture that luminous flares from regions hosting forming high-mass star may be an observational implication of the fragmentation of their accretion disks.