Protoplanetary Disk Size under Nonideal Magnetohydrodynamics: A General Formalism with Inclined Magnetic Field

Lee 李, Yueh-Ning 悅寧; Ray, Barshan; Marchand, Pierre; Hennebelle, Patrick

doi:10.3847/2041-8213/ad192a

Cited by 3 publications

(9 citation statements)

References 19 publications

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“…These observations probe the large-scale molecular clouds, filaments, and cores whose magnetic field imprint could be inherently different than the magnetic fields near a protostellar disk. Additionally, a magnetic field-density relation recently derived by Lee et al (2024) for inside a collapsing protostellar envelope is explored in Appendix D. The magnetic field strength derived from this relation is compatible with our estimates; however, it needs to be further investigated due to discrepancies in the model presumptions.…”

Section: Quantities and Relations Used For The Ambipolar Diffusivity ...supporting

confidence: 62%

“…where k B is the Boltzmann constant, μ m = 2.37 is the mean molecular weight for a molecular gas with solar metallicity, and m H is the mass of a hydrogen atom. The isothermal sound speed is estimated to be C s = 833.0 ± 19.5 m s −1 , which is higher than the typically assumed value of 200 m s −1 (e.g., Lee et al 2021bLee et al , 2024.…”

Section: Temperature Distribution Of the Diskmentioning

confidence: 61%

“…The equation describing the disk radius due to ambipolar diffusion first presented by Hennebelle et al (2016), and later by Lee et al (2021bLee et al ( , 2024, make a number of simplifications. Here, we derive a new relationship between the physical properties at the disk-envelope interface to the ambipolar diffusivity coefficient, in order to better compare to more generalized models that are used to fit observations, as in our case for HOPS-370.…”

Section: Appendix a Derivation Of The Ambipolar Diffusivity Coefficie...mentioning

confidence: 99%

“…In this paper, we aim to understand the role of ambipolar diffusion in protostellar disk formation by using a methodology first developed by Hennebelle et al (2016), and later revisited by Lee et al (2021bLee et al ( , 2024. This methodology leads to an analytical equation describing the expected protostellar properties, in particular the protostellar disk radius, due to ambipolar diffusion (Hennebelle et al 2016).…”

Section: Introductionmentioning

confidence: 99%

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The First Estimation of the Ambipolar Diffusivity Coefficient from Multi-scale Observations of the Class 0/I Protostar, HOPS-370

Thieme,

Lai,

Lee

et al. 2024

ApJ

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Protostars are born in magnetized environments. As a consequence, the formation of protostellar disks can be suppressed by the magnetic field, efficiently removing the angular momentum of the infalling material. Nonideal MHD effects are proposed as one way to allow protostellar disks to form. Thus, it is important to understand their contributions to observations of protostellar systems. We derive an analytical equation to estimate the ambipolar diffusivity coefficient at the edge of the protostellar disk in the Class 0/I protostar, HOPS-370, for the first time, under the assumption that the disk radius is set by ambipolar diffusion. Using previous results of the protostellar mass, disk mass, disk radius, density and temperature profiles, and magnetic field strength, we estimate the ambipolar diffusivity coefficient to be 1.7 − 1.4 + 1.5 × 10 19 cm 2 s − 1 . We quantify the contribution of ambipolar diffusion by estimating its dimensionless Elsässer number to be ∼ 1.7 − 1.0 + 1.0 , indicating its dynamical importance in this region. We compare our results to those of the chemical calculations of the ambipolar diffusivity coefficient using the Non-Ideal Magnetohydrodynamics Coefficients and Ionization Library, which are consistent with our results. In addition, we compare our derived ambipolar diffusivity coefficient to the diffusivity coefficients for ohmic dissipation and the Hall effect, and find ambipolar diffusion is dominant in our density regime. These results demonstrate a new methodology to understand nonideal MHD effects in observations of protostellar disks. More detailed modeling of the magnetic field, envelope, and microphysics, along with a larger sample of protostellar systems, is needed to further understand the contributions of nonideal MHD.

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Section: Quantities and Relations Used For The Ambipolar Diffusivity ...supporting

confidence: 62%

Section: Temperature Distribution Of the Diskmentioning

confidence: 61%

Section: Appendix a Derivation Of The Ambipolar Diffusivity Coefficie...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The First Estimation of the Ambipolar Diffusivity Coefficient from Multi-scale Observations of the Class 0/I Protostar, HOPS-370

Thieme,

Lai,

Lee

et al. 2024

ApJ

Self Cite

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“…Success in the study of weakly nonlinear waves for an extremely wide range of different hydrodynamic situations is associated with awareness of the feature of the universality of weakly nonlinear models. As for researchers outside of Russia, their interest in analytical solutions lately was mainly focused on problems of astrophysics, where processes with an infinitely large magnetic Reynolds number are considered [58] as well as numerous other applications (see, for instance, [59][60][61]).…”

Section: Historical Overviewmentioning

confidence: 99%

Dynamics of Fluids in the Cavity of a Rotating Body: A Review of Analytical Solutions

Gurchenkov,

Matveev

2024

Physics

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Since the middle of the 20th century, an understanding of the diversity of the natural magnetohydrodynamic phenomena surrounding us has begun to emerge. Magnetohydrodynamic nature manifests itself in such seemingly heterogeneous processes as the flow of water in the world’s oceans, the movements of Earth’s liquid core, the dynamics of the solar magnetosphere and galactic electromagnetic fields. Their close relationship and multifaceted influence on human life are becoming more and more clearly revealed. The study of these phenomena requires the development of theory both fundamental and analytical, unifying a wide range of phenomena, and specialized areas that describe specific processes. The theory of translational fluid motion is well developed, but for most natural phenomena, this condition leads to a rather limited model. The fluid motion in the cavity of a rotating body such that the Coriolis forces are significant has been studied much less. A distinctive feature of the problems under consideration is their significant nonlinearity, (i.e., the absence of a linear approximation that allows one to obtain nontrivial useful results). From this point of view, the studies presented here were selected. This review presents studies on the movements of ideal and viscous fluids without taking into account electromagnetic phenomena (non-conducting, non-magnetic fluid) and while taking them into account (conducting fluid). Much attention is payed to the macroscopic movements of sea water (conducting liquid) located in Earth’s magnetic field, which spawns electric currents and, as a result, an induced magnetic field. Exploring the processes of generating magnetic fields in the moving turbulent flows of conducting fluid in the frame of dynamic systems with distributed parameters allows better understanding of the origin of cosmic magnetic fields (those of planets, stars, and galaxies). Various approaches are presented for rotational and librational movements. In particular, an analytical solution of three-dimensional unsteady magnetohydrodynamic equations for problems in a plane-parallel configuration is presented.

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Early Planet Formation in Embedded Disks (eDisk). XV. Influence of Magnetic Field Morphology in Dense Cores on Sizes of Protostellar Disks

Yen,

Williams,

Sai

et al. 2024

ApJ

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The magnetic field of a molecular cloud core may play a role in the formation of circumstellar disks in the core. We present magnetic field morphologies in protostellar cores of 16 targets in the Atacama Large Millimeter/submillimeter Array large program “Early Planet Formation in Embedded Disks (eDisk),” which resolved their disks with 7 au resolutions. The 0.1 pc scale magnetic field morphologies were inferred from the James Clerk Maxwell Telescope POL-2 observations. The mean orientations and angular dispersions of the magnetic fields in the dense cores are measured and compared with the radii of the 1.3 mm continuum disks and the dynamically determined protostellar masses from the eDisk program. We observe a significant correlation between the disk radii and the stellar masses. We do not find any statistically significant dependence of the disk radii on the projected misalignment angles between the rotational axes of the disks and the magnetic fields in the dense cores, nor on the angular dispersions of the magnetic fields within these cores. However, when considering the projection effect, we cannot rule out a positive correlation between disk radii and misalignment angles in three-dimensional space. Our results suggest that the morphologies of magnetic fields in dense cores do not play a dominant role in the disk formation process. Instead, the sizes of protostellar disks may be more strongly affected by the amount of mass that has been accreted onto star+disk systems, and possibly other parameters, for example, magnetic field strength, core rotation, and magnetic diffusivity.

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Protoplanetary Disk Size under Nonideal Magnetohydrodynamics: A General Formalism with Inclined Magnetic Field

Cited by 3 publications

References 19 publications

The First Estimation of the Ambipolar Diffusivity Coefficient from Multi-scale Observations of the Class 0/I Protostar, HOPS-370

The First Estimation of the Ambipolar Diffusivity Coefficient from Multi-scale Observations of the Class 0/I Protostar, HOPS-370

Dynamics of Fluids in the Cavity of a Rotating Body: A Review of Analytical Solutions

Early Planet Formation in Embedded Disks (eDisk). XV. Influence of Magnetic Field Morphology in Dense Cores on Sizes of Protostellar Disks

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