TY - JOUR
T1 - Misalignment of magnetic fields, outflows, and discs in star-forming clouds
AU - Machida, Masahiro N.
AU - Hirano, Shingo
AU - Kitta, Hideyuki
N1 - Funding Information:
The authors would like to thank B. Riaz, K. Tomida, and S. Takasao for their helpful contributions. We also thank the referee R. Banerjee for careful reading and useful comment on this paper. This research used the computational resources of the HPCI system provided by Cyber Science Centre, Tohoku University, and Cybermedia Center, Osaka University through the HPCI System Research Project (Project ID: hp170047, hp180001, hp190035). The simulations reported in this paper were also performed by the 2018 and 2019 Koubo Kadai on Earth Simulator (NEC SX-ACE) at JAMSTEC. This work was supported by a JSPS Research Fellowship for SH and JSPS KAKENHI Grant Numbers 18J01296 for SH and by 17K05387, 17H06360, and 17H02869, 17KK0096 for MNM.
Funding Information:
The authors would like to thank B. Riaz, K. Tomida, and S. Takasao for their helpful contributions. We also thank the referee R. Banerjee for careful reading and useful comment on this paper. This research used the computational resources of the HPCI system provided by Cyber Science Centre, Tohoku University, and Cybermedia Center, Osaka University through the HPCI System Research Project (Project ID: hp170047, hp180001, hp190035). The simulations reported in this paper were also performed by the 2018
Publisher Copyright:
© 2019 The Author(s).
PY - 2020/1/1
Y1 - 2020/1/1
N2 - Using resistive magnetohydrodynamics simulations, the propagation of protostellar jets, the formation of circumstellar discs, and the configuration of magnetic fields are investigated from the pre-stellar cloud phase until ∼500 yr after protostar formation. As the initial state, we prepare magnetized rotating clouds, in which the rotation axis is misaligned with the global magnetic field by an angle θ0. We calculate the cloud evolution for nine models with different θ0 (= 0°, 5°, 10°, 30°, 45°, 60°, 80°, 85°, 90°). Our simulations show that there is no significant difference in the physical quantities of the protostellar jet, such as the mass and momentum, among the models except for the model with θ0 = 90°. On the other hand, the directions of the jet, disc normal, and magnetic field are never aligned with each other during the early phase of star formation except for the model with θ0 = 0°. Even when the rotation axis of the pre-stellar cloud is slightly inclined to the global magnetic field, the directions of the jet, disc normal, and local magnetic field differ considerably, and they randomly change over time. Our results indicate that it is very difficult to extract any information from the observations of the directions of the outflow, disc, and magnetic field at the scale of < 1000 au. Thus, we cannot use such observations to derive any restrictions on the star formation process.
AB - Using resistive magnetohydrodynamics simulations, the propagation of protostellar jets, the formation of circumstellar discs, and the configuration of magnetic fields are investigated from the pre-stellar cloud phase until ∼500 yr after protostar formation. As the initial state, we prepare magnetized rotating clouds, in which the rotation axis is misaligned with the global magnetic field by an angle θ0. We calculate the cloud evolution for nine models with different θ0 (= 0°, 5°, 10°, 30°, 45°, 60°, 80°, 85°, 90°). Our simulations show that there is no significant difference in the physical quantities of the protostellar jet, such as the mass and momentum, among the models except for the model with θ0 = 90°. On the other hand, the directions of the jet, disc normal, and magnetic field are never aligned with each other during the early phase of star formation except for the model with θ0 = 0°. Even when the rotation axis of the pre-stellar cloud is slightly inclined to the global magnetic field, the directions of the jet, disc normal, and local magnetic field differ considerably, and they randomly change over time. Our results indicate that it is very difficult to extract any information from the observations of the directions of the outflow, disc, and magnetic field at the scale of < 1000 au. Thus, we cannot use such observations to derive any restrictions on the star formation process.
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U2 - 10.1093/mnras/stz3159
DO - 10.1093/mnras/stz3159
M3 - Article
AN - SCOPUS:85079600357
VL - 491
SP - 2180
EP - 2197
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 2
ER -