MHD Simulations of Dense Core Collision

Kinoshita, Shinichi. W.; Nakamura, Fúmitaka

doi:10.3847/1538-4357/ac8c95

Cited by 6 publications

(14 citation statements)

References 43 publications

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“…As isolated cores, these simulations do not accurately reflect the relation between inner regions of the cores and inflow(s) from the larger clump scales. On the other hand, simulations considering interactions between cores can explain observations of asymmetric streamers at >1000 au scales (e.g., Kinoshita & Nakamura 2022;Yano et al 2023), like in W33A where a single spiral feature is observed. Therefore, whether the streamers in G336.01-0.82 originated from gravitational instabilities, large-scale inflows and/or interaction with other cores remain unclear.…”

Section: Infall Along Streamersmentioning

confidence: 97%

Digging into the Interior of Hot Cores with ALMA: Spiral Accretion into the High-mass Protostellar Core G336.01–0.82

Olguin,

Sanhueza,

Chen

et al. 2023

ApJL

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We observed the high-mass star-forming core G336.01–0.82 at 1.3 mm and 0.″05 (∼150 au) angular resolution with the Atacama Large Millimeter/submillimeter Array (ALMA) as part of the Digging into the Interior of Hot Cores with ALMA survey. These high-resolution observations reveal two spiral streamers feeding a circumstellar disk at opposite sides in great detail. Molecular line emission from CH3OH shows velocity gradients along the streamers consistent with infall. Similarly, a flattened envelope model with rotation and infall implies a mass larger than 10 M ☉ for the central source and a centrifugal barrier of 300 au. The location of the centrifugal barrier is consistent with local peaks in the continuum emission. We argue that gas brought by the spiral streamers is accumulating at the centrifugal barrier, which can result in future accretion burst events. A total high infall rate of ∼4 × 10−4 M ☉ yr−1 is derived by matching models to the observed velocity gradient along the streamers. Their contribution accounts for 20%–50% the global infall rate of the core, indicating streamers play an important role in the formation of high-mass stars.

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Section: Infall Along Streamersmentioning

confidence: 97%

Digging into the Interior of Hot Cores with ALMA: Spiral Accretion into the High-mass Protostellar Core G336.01–0.82

Olguin,

Sanhueza,

Chen

et al. 2023

ApJL

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“…The numerical code is essentially the same as that of Kinoshita & Nakamura (2022). We use the numerical code Enzo 4 , an MHD adaptive mesh refinement (AMR) code (Bryan et al 2014).…”

Section: Numerical Codementioning

confidence: 99%

Unveiling the Dynamics of Dense Cores in Cluster-forming Clumps: A 3D Magnetohydrodynamics Simulation Study of Angular Momentum and Magnetic Field Properties

Kinoshita,

Nakamura

2023

ApJ

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We conducted isothermal magnetohydrodynamics simulations with self-gravity to investigate the properties of dense cores in cluster-forming clumps. Two different setups were explored: a single rotating clump and colliding clumps. We focused on determining the extent to which the rotation and magnetic field of the parental clump are inherited by the formed dense cores. Our statistical analysis revealed that the alignment between the angular momentum of dense cores, L core , and the rotational axis of the clump is influenced by the strength of turbulence and the simulation setup. In single rotating clumps, we found that L core tends to align with the clump’s rotational axis if the initial turbulence is weak. In colliding clumps, however, this alignment does not occur, regardless of the initial turbulence strength. This misalignment in colliding clumps is due to the induced turbulence from the collision and the isotropic gas inflow into dense cores. Our analysis of colliding clumps also revealed that the magnetic field globally bends along the shock-compressed layer, and the mean magnetic field of dense cores, B core , aligns with it. Both in single rotating clumps and colliding clumps, we found that the angle between B core and L core is generally random, regardless of the clump properties. We also analyzed the dynamical states of the formed cores and found a higher proportion of unbound cores in colliding clumps. In addition, the contribution of rotational energy was only approximately 5% of the gravitational energy, regardless of the model parameters for both single and colliding cases.

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“…The phenomenon of core collision and merging has been shown to generate asymmetric structures (Kuffmeier et al 2021;Hanawa et al 2022;Kinoshita & Nakamura 2022). Recent simulations have further demonstrated that core collisions can explain several characteristics that are challenging to account for solely with the isolated core collapse model.…”

Section: Introductionmentioning

confidence: 99%

“…Hence, it is crucial to investigate the processes and resulting structures that emerge during core collisions. Kinoshita & Nakamura (2022) conducted magnetohydrodynamic simulations to study the collision of two equally massive, gravitationally stable prestellar cores. Their work illustrated that core collisions lead to the formation of single or multiple protostars.…”

Section: Introductionmentioning

confidence: 99%

Dense Core Collisions in Molecular Clouds: Formation of Streamers and Binary Stars

Yano,

Nakamura,

Kinoshita

2024

ApJ

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Dense core collisions, previously regarded as minor in star formation, are proposed to play a significant role in structure formation around protostellar envelopes and binary formation. Using archival data of nearby star-forming regions, we determine the frequencies of core collisions. Our calculations reveal that a typical core is likely to undergo multiple interactions with other cores throughout its lifetime. To further investigate the core collision process, we employ adaptive mesh refinement hydrodynamic simulations with sink particles. Our simulations demonstrate that following the formation of a protostar within a gravitationally unstable core, the merging core’s accreting gas gives rise to a rotationally supported circumstellar disk. Meanwhile, the region compressed by the shock between the cores develops into asymmetric arms that connect with the disk. Gas along these arms tends to migrate inward, ultimately falling toward the protostar. One of the arms, a remnant of the shock-compressed region, dominates over the second core gas, potentially exhibiting a distinct chemical composition. This is consistent with recent findings of large-scale streamers around protostars. Additionally, we found that collisions with velocities of ∼1.5 km s−1 result in the formation of a binary system, as evidenced by the emergence of a sink particle within the dense section of the shocked layer. Overall, dense core collisions are highlighted as a critical process in creating 103 au-scale streamers around protostellar systems and binary stars.

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MHD Simulations of Dense Core Collision

Cited by 6 publications

References 43 publications

Digging into the Interior of Hot Cores with ALMA: Spiral Accretion into the High-mass Protostellar Core G336.01–0.82

Digging into the Interior of Hot Cores with ALMA: Spiral Accretion into the High-mass Protostellar Core G336.01–0.82

Unveiling the Dynamics of Dense Cores in Cluster-forming Clumps: A 3D Magnetohydrodynamics Simulation Study of Angular Momentum and Magnetic Field Properties

Dense Core Collisions in Molecular Clouds: Formation of Streamers and Binary Stars

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