RADIATION MAGNETOHYDRODYNAMIC SIMULATIONS OF PROTOSTELLAR COLLAPSE: PROTOSTELLAR CORE FORMATION

By K. Tomida, Kohji Tomisaka, Tomoaki Matsumoto, Y. Hori, S. Okuzumi, Masahiro N. Machida, K. Saigo. 2012

165 citations recorded by the source corpus.

We report the first three-dimensional radiation magnetohydrodynamic (RMHD) simulations of protostellar collapse with and without Ohmic dissipation. We take into account many physical processes required to study star formation processes, including a realistic equation of state. We follow the evolution from molecular cloud cores until protostellar cores are formed with sufficiently high resolutions without introducing a sink particle. The physical processes involved in the simulations and adopted numerical methods are described in detail. We can calculate only about one year after the formation of the protostellar cores with our direct three-dimensional RMHD simulations because of the extremely short timescale in the deep interior of the formed protostellar cores, but successfully describe the early phase of star formation processes. The thermal evolution and the structure of the first and second (protostellar) cores are consistent with previous one-dimensional simulations using full radiation transfer, but differ considerably from preceding multi-dimensional studies with the barotropic approximation. The protostellar cores evolve virtually spherically symmetric in the ideal MHD models because of efficient angular momentum transport by magnetic fields, but Ohmic dissipation enables the formation of the circumstellar disks in the vicinity of the protostellar cores as in previous MHD studies with the barotropic approximation. The formed disks are still small (less than 0.35 AU) because we simulate only the earliest evolution. We also confirm that two different types of outflows are naturally launched by magnetic fields from the first cores and protostellar cores in the resistive MHD models.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/5b47a9fdceb3c1ed1c902ab009d7d9825c2fe949

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In Astronomy and Astrophysics

Citations in the corpus

On the diversity and statistical properties of protostellar discs (2018, background): “Similarly, introducing Ohmic diffusion only produces small discs unless an anomalously high resistivity is used (Shu et al. 2006; Krasnopolsky et al. 2010; Dapp & Basu 2010; Machida et al. 2011; Tomida et al. 2013; Wurster et al. 2016).”
Global Simulations of the Inner Regions of Protoplanetary Disks with Comprehensive Disk Microphysics (2017, methodology): “Nevertheless, it is physically intuitive to distinguish the two regimes, as is widely adopted in other contexts such as star formation (e.g., Seifried et al. 2012; Tomida et al. 2013).”
RADIATION MAGNETOHYDRODYNAMIC SIMULATIONS OF PROTOSTELLAR COLLAPSE: NONIDEAL MAGNETOHYDRODYNAMIC EFFECTS AND EARLY FORMATION OF CIRCUMSTELLAR DISKS (2015, methodology): “For example, nonideal MHD effects such as ohmic dissipation and ambipolar diffusion can redistribute magnetic flux and suppress angular momentum transport (Dapp & Basu 2010; Machida & Matsumoto 2011; Machida et al. 2011a; Dapp et al. 2012; Machida & Hosokawa 2013; Tomida et al. 2013).”