Turn up the light: Radiative efficiency of protostars at birth

Fuente: arXiv
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Main Authors: Bhandare, Asmita, Ahmad, Adnan Ali, Commerçon, Benoît
Format: Preprint
Published: 2025
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author Bhandare, Asmita
Ahmad, Adnan Ali
Commerçon, Benoît
author_facet Bhandare, Asmita
Ahmad, Adnan Ali
Commerçon, Benoît
contents Early stages of stellar birth comprise of a two-step process involving the formation of two hydrostatic cores. The second step of gravitational collapse sets the radiative efficiency and accretion rate of the young protostar. These two parameters, of prime importance for protostellar evolution, dictate the luminosities and thus play a key role in deciphering the current discrepancy between observational surveys and theoretical models. In this letter, we provide quantitative estimates on the evolution of the radiative efficiency and accretion rate obtained from self-consistent, high-resolution, radiative hydrodynamic simulations performed using the codes PLUTO and RAMSES. The main highlight of our result is that the radiative efficiency reaches unity, that is, supercriticality, relatively quickly after protostellar birth. Supercriticality at the accretion shock is a necessary condition for cold accretion. Our results thus support a rapid transition to the cold accretion scenario, which is one of the assumptions used in Pre-Main Sequence (PMS) models working towards solutions to explain observational data. We briefly discuss the implications of the time evolution of the radiative efficiency factor in the context of the luminosity problem, the Protostellar Luminosity Function (PLF), PMS evolution, accurate sink properties, and the stellar Initial Mass Function (IMF).
format Preprint
id arxiv_https___arxiv_org_abs_2509_15009
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Turn up the light: Radiative efficiency of protostars at birth
Bhandare, Asmita
Ahmad, Adnan Ali
Commerçon, Benoît
Solar and Stellar Astrophysics
Astrophysics of Galaxies
Early stages of stellar birth comprise of a two-step process involving the formation of two hydrostatic cores. The second step of gravitational collapse sets the radiative efficiency and accretion rate of the young protostar. These two parameters, of prime importance for protostellar evolution, dictate the luminosities and thus play a key role in deciphering the current discrepancy between observational surveys and theoretical models. In this letter, we provide quantitative estimates on the evolution of the radiative efficiency and accretion rate obtained from self-consistent, high-resolution, radiative hydrodynamic simulations performed using the codes PLUTO and RAMSES. The main highlight of our result is that the radiative efficiency reaches unity, that is, supercriticality, relatively quickly after protostellar birth. Supercriticality at the accretion shock is a necessary condition for cold accretion. Our results thus support a rapid transition to the cold accretion scenario, which is one of the assumptions used in Pre-Main Sequence (PMS) models working towards solutions to explain observational data. We briefly discuss the implications of the time evolution of the radiative efficiency factor in the context of the luminosity problem, the Protostellar Luminosity Function (PLF), PMS evolution, accurate sink properties, and the stellar Initial Mass Function (IMF).
title Turn up the light: Radiative efficiency of protostars at birth
topic Solar and Stellar Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2509.15009