TY - JOUR
T1 - Origin of misalignments
T2 - Protostellar jet, outflow, circumstellar disc, and magnetic field
AU - Hirano, Shingo
AU - Machida, Masahiro N.
N1 - Funding Information:
The authors would like to thank Hideyuki Kitta, Basmah Riaz, Kengo Tomida, and Kohji Tomisaka for the stimulating discussions. This research used the computational resources of the HPCI system provided by (Cyber Sciencecenter, Tohoku University; Cybermedia Center, Osaka University through the HPCI System Research Project (Project ID: hp170047, hp180001). Simulations reported in this paper were also performed by 2017 and 2018 Koubo Kadai on Earth Simulator (NEC SX-ACE) at JAMSTEC. This work was supported by Japan Society for the Promotion of Science (JSPS) Research Fellow to SH and by JSPS KAKENHI Grant Numbers 18J01296 to SH and 17K05387, 17H06360, and 17H02869 to MNM.
Funding Information:
The authors would like to thank Hideyuki Kitta, Basma Riaz, Kengo Tomida, and Kohji Tomisaka for the stimulating discussions. This research used the computational resources of the HPCI system provided by (Cyber Sciencecenter, Tohoku University; Cybermedia Center, Osaka University through the HPCI System Research Project (Project ID: Hp170047, hp180001). Simulations reported in this paper were also performed by 2017 and 2018 Koubo Kadai on Earth Simulator (NEC SX-ACE) at JAMSTEC. This work was supported by Japan Society for the Promotion of Science (JSPS) Research Fellow to SH and by JSPS KAKENHI Grant Numbers 18J01296 to SH and 17K05387, 17H06360, and 17H02869 to MNM.
Publisher Copyright:
© 2019 The Author(s).
PY - 2019/3/13
Y1 - 2019/3/13
N2 - Recent observations uncover various phenomena around the protostar such as misalignment between the outflow and magnetic field, precession of the jet, and time variability of the ejected clumps, whose origins are under debate. We perform a three-dimensional resistive magnetohydrodynamics simulation of the protostar formation in a star-forming core whose rotation axis is tilted at an angle 45. with respect to the initial magnetic field, in which the protostar is resolved with a spatial resolution of 0.01 au. In low-dense outer region, the prestellar core contracts along the magnetic field lines due to the flux freezing. In high-dense inner region, on the other hand, the magnetic dissipation becomes efficient and weakens the magnetic effects when the gas number density exceeds about 1011 cm-3 Then, the normal direction of the flattened disc is aligned with the angular momentum vector. The outflow, jet, and protostellar ejection are driven from different scales of the circumstellar disc and spout in different directions normal to the warped disc. These axes do not coincide with the global magnetic field direction and vary with time. This study demonstrates that a couple of misalignment natures reported by observations can be simultaneously reproduced only by assuming the star-forming core rotating around a different direction from the magnetic field.
AB - Recent observations uncover various phenomena around the protostar such as misalignment between the outflow and magnetic field, precession of the jet, and time variability of the ejected clumps, whose origins are under debate. We perform a three-dimensional resistive magnetohydrodynamics simulation of the protostar formation in a star-forming core whose rotation axis is tilted at an angle 45. with respect to the initial magnetic field, in which the protostar is resolved with a spatial resolution of 0.01 au. In low-dense outer region, the prestellar core contracts along the magnetic field lines due to the flux freezing. In high-dense inner region, on the other hand, the magnetic dissipation becomes efficient and weakens the magnetic effects when the gas number density exceeds about 1011 cm-3 Then, the normal direction of the flattened disc is aligned with the angular momentum vector. The outflow, jet, and protostellar ejection are driven from different scales of the circumstellar disc and spout in different directions normal to the warped disc. These axes do not coincide with the global magnetic field direction and vary with time. This study demonstrates that a couple of misalignment natures reported by observations can be simultaneously reproduced only by assuming the star-forming core rotating around a different direction from the magnetic field.
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U2 - 10.1093/mnras/stz740
DO - 10.1093/mnras/stz740
M3 - Article
AN - SCOPUS:85064124794
SN - 0035-8711
VL - 485
SP - 4667
EP - 4674
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -