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Autori principali: Cusack, Matt T., Clark, Paul C., Rice, Ken, Glover, Simon C. O., Klessen, Ralf S., Whitworth, Anthony P., Priestley, Felix D., Duarte-Cabral, Ana
Natura: Preprint
Pubblicazione: 2026
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Accesso online:https://arxiv.org/abs/2605.05377
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author Cusack, Matt T.
Clark, Paul C.
Rice, Ken
Glover, Simon C. O.
Klessen, Ralf S.
Whitworth, Anthony P.
Priestley, Felix D.
Duarte-Cabral, Ana
author_facet Cusack, Matt T.
Clark, Paul C.
Rice, Ken
Glover, Simon C. O.
Klessen, Ralf S.
Whitworth, Anthony P.
Priestley, Felix D.
Duarte-Cabral, Ana
contents We present high-resolution zoom-in simulations of molecular clouds exposed to an interstellar radiation field and cosmic ray ionisation rate up to 1000 times stronger than that of the solar neighbourhood. We detail the evolution of the accretion discs that form around the first protostar in each simulation, for a total of 7 discs, for up to 100 kyr. The use of a zoom-in procedure allows for the au-scale discs to be well resolved (with resolution < 0.25 au) whilst retaining the structure of the wider parsec-scale molecular cloud. We find that discs exposed to a stronger radiation field tend to be more massive, hotter and denser. Similarly, their host stars grow to become more massive as a result of accreting more rapidly from their surroundings. All the discs show evidence of recurrent instability during the simulations, but only some of them fragment. We investigate whether stability metrics, such as the Toomre $Q$, $α$ viscosity, and $β$ cooling parameter, can predict fragmentation by calculating them just before the discs fragment. We find that the metrics are generally unable to do so, as the discs appear stable even up to a few hundred years before fragmenting. In solar-like environments fragments are typically of planetary mass and often migrate to the centre of the disc, whereas fragments in a high-radiation environment are massive ($\rm > 0.1 \, M_\odot$) and fully disrupt/accrete from the progenitor disc. We conclude that the evolution and properties of circumstellar discs depend on both their radiation and physical environment.
format Preprint
id arxiv_https___arxiv_org_abs_2605_05377
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle The Impact of Radiation Environment on the Evolution and Fragmentation of Protostellar Discs
Cusack, Matt T.
Clark, Paul C.
Rice, Ken
Glover, Simon C. O.
Klessen, Ralf S.
Whitworth, Anthony P.
Priestley, Felix D.
Duarte-Cabral, Ana
Solar and Stellar Astrophysics
We present high-resolution zoom-in simulations of molecular clouds exposed to an interstellar radiation field and cosmic ray ionisation rate up to 1000 times stronger than that of the solar neighbourhood. We detail the evolution of the accretion discs that form around the first protostar in each simulation, for a total of 7 discs, for up to 100 kyr. The use of a zoom-in procedure allows for the au-scale discs to be well resolved (with resolution < 0.25 au) whilst retaining the structure of the wider parsec-scale molecular cloud. We find that discs exposed to a stronger radiation field tend to be more massive, hotter and denser. Similarly, their host stars grow to become more massive as a result of accreting more rapidly from their surroundings. All the discs show evidence of recurrent instability during the simulations, but only some of them fragment. We investigate whether stability metrics, such as the Toomre $Q$, $α$ viscosity, and $β$ cooling parameter, can predict fragmentation by calculating them just before the discs fragment. We find that the metrics are generally unable to do so, as the discs appear stable even up to a few hundred years before fragmenting. In solar-like environments fragments are typically of planetary mass and often migrate to the centre of the disc, whereas fragments in a high-radiation environment are massive ($\rm > 0.1 \, M_\odot$) and fully disrupt/accrete from the progenitor disc. We conclude that the evolution and properties of circumstellar discs depend on both their radiation and physical environment.
title The Impact of Radiation Environment on the Evolution and Fragmentation of Protostellar Discs
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2605.05377