Issue |
A&A
Volume 670, February 2023
|
|
---|---|---|
Article Number | A38 | |
Number of page(s) | 11 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361/202243493 | |
Published online | 02 February 2023 |
Non-ideal magnetohydrodynamics of self-gravitating filaments
1
Departamento de Astronomía, Facultad Ciencias Físicas y Matemáticas, Universidad de Concepción,
Av. Esteban Iturra s/n Barrio Universitario, Casilla 160,
Concepción, Chile
e-mail: ngutierrezv@udec.cl
2
Centre for Astrochemical Studies, Max-Planck-Institut für Extraterrestrische Physik,
Gießnbachstr. 1,
85749
Garching bei München, Germany
3
Dipartimento di Fisica “G. Occhialini”, Universitá degli Studi Milano-Bicocca,
Piazza della Scienza 3,
20126
Milano, Italy
4
INFN, Sezione di Milano-Bicocca,
Piazza della Scienza 3,
20126
Milano, Italy
5
INAF - Osservatorio Astrofisico di Arcetri,
Largo E. Fermi 5,
50125
Firenze, Italy
Received:
7
March
2022
Accepted:
2
November
2022
Context. Filaments have been studied in detail through observations and simulations. A range of numerical works have separately investigated how chemistry and diffusion effects, as well as magnetic fields and their structure impact the gas dynamics of the filament. However, non-ideal effects have hardly been explored thus far.
Aims. We investigate how non-ideal magnetohydrodynamic (MHD) effects, combined with a simplified chemical model affect the evolution and accretion of a star-forming filament.
Methods. We modeled an accreting self-gravitating turbulent filament using LEMONGRAB, a one-dimensional (1D) non-ideal MHD code that includes chemistry. We explore the influence of non-ideal MHD, the orientation and strength of the magnetic field, and the cosmic ray ionization rate, on the evolution of the filament, with particular focus on the width and accretion rate.
Results. We find that the filament width and the accretion rate are determined by the magnetic field properties, including the initial strength, the coupling with the gas controlled by the cosmic ray ionization rate, and the orientation of the magnetic field with respect to the accretion flow direction. Increasing the cosmic-ray ionization rate leads to a behavior closer to that of ideal MHD, reducing the magnetic pressure support and, hence, damping the accretion efficiency with a consequent broadening of the filament width. For the same reason, we obtained a narrower width and a larger accretion rate when we reduced the initial magnetic field strength. Overall, while these factors affect the final results by approximately a factor of 2, removing the non-ideal MHD effects results in a much greater variation (up to a factor of 7).
Conclusions. The inclusion of non-ideal MHD effects and the cosmic-ray ionization is crucial for the study of self-gravitating filaments and in determining critical observable quantities, such as the filament width and accretion rate.
Key words: stars: formation / magnetohydrodynamics (MHD) / methods: numerical / ISM: clouds
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This article is published in open access under the Subscribe-to-Open model. Subscribe to A&A to support open access publication.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.