TY - JOUR
T1 - Different modes of star formation
T2 - Gravitational collapse of magnetically subcritical cloud
AU - Machida, Masahiro N.
AU - Higuchi, Koki
AU - Okuzumi, Satoshi
N1 - Funding Information:
We have benefited greatly from discussions with K. Tomisaka, K. Tomida, T. Nakano and S. Basu. We also thank the reviewer for many useful comments on this paper. This work was supported by JSPS KAKENHI Grant Numbers JP25400232, JP15K05032 and JP17K05387, JP17H06360, 17H02869. This research used computational resources from the high-performance computing infrastructure (HPCI) system provided by the Cyberscience Center, Tohoku University, and the Cybermedia Center, Osaka University, and the Earth simulator, JAMSTEC through the HPCI System Research Project (Project ID: hp150092, hp160079, hp170047). Simulations were also performed by 2017 Koubo Kadai on Earth Simulator (NEC SX-ACE) at JAMSTEC
Publisher Copyright:
© 2017 The Author(s).
PY - 2018/1
Y1 - 2018/1
N2 - Star formation in magnetically subcritical clouds is investigated using a three-dimensional non-ideal magnetohydrodynamic simulation. Since rapid cloud collapse is suppressed until the magnetic flux is sufficiently removed from the initially magnetically subcritical cloud by ambipolar diffusion, it takes ≳5-10 tff to form a protostar, where tff is the freefall time-scale of the initial cloud. The angular momentum of the star-forming cloud is efficiently transferred to the interstellar medium before the rapid collapse begins, and the collapsing cloud has a very low angular momentum. Unlike the magnetically supercritical case, no large-scale lowvelocity outflow appears in such a collapsing cloud due to the short lifetime of the first core. Following protostar formation, a very weak high-velocity jet, which has a small momentum and might disappear at a later time, is driven near the protostar, while the circumstellar disc does not grow during the early mass accretion phase. The results show that the star formation process in magnetically subcritical clouds is qualitatively different from that in magnetically supercritical clouds.
AB - Star formation in magnetically subcritical clouds is investigated using a three-dimensional non-ideal magnetohydrodynamic simulation. Since rapid cloud collapse is suppressed until the magnetic flux is sufficiently removed from the initially magnetically subcritical cloud by ambipolar diffusion, it takes ≳5-10 tff to form a protostar, where tff is the freefall time-scale of the initial cloud. The angular momentum of the star-forming cloud is efficiently transferred to the interstellar medium before the rapid collapse begins, and the collapsing cloud has a very low angular momentum. Unlike the magnetically supercritical case, no large-scale lowvelocity outflow appears in such a collapsing cloud due to the short lifetime of the first core. Following protostar formation, a very weak high-velocity jet, which has a small momentum and might disappear at a later time, is driven near the protostar, while the circumstellar disc does not grow during the early mass accretion phase. The results show that the star formation process in magnetically subcritical clouds is qualitatively different from that in magnetically supercritical clouds.
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U2 - 10.1093/mnras/stx2589
DO - 10.1093/mnras/stx2589
M3 - Article
AN - SCOPUS:85045890668
SN - 0035-8711
VL - 473
SP - 3080
EP - 3094
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 3
ER -