期刊
ASTROPHYSICAL JOURNAL
卷 716, 期 2, 页码 1541-1550出版社
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/716/2/1541
关键词
accretion, accretion disks; ISM: clouds; ISM: magnetic fields; magnetohydrodynamics (MHD)
资金
- Theoretical Institute for Advanced Research in Astrophysics (TIARA)
- National Science Council of Taiwan [NSC97-2112-M-001-018-MY3]
- NASA ATP [NNG06GJ33G]
- Origins [NNG05GJ49G, NNX10AH30G]
Disk formation in magnetized cloud cores is hindered by magnetic braking. Previous work has shown that for realistic levels of core magnetization, the magnetic field suppresses the formation of rotationally supported disks during the protostellar mass accretion phase of low-mass star formation both in the ideal MHD limit and in the presence of ambipolar diffusion for typical rates of cosmic-ray ionization. Additional effects, such as ohmic dissipation, the Hall effect, and protostellar outflow, are needed to weaken the magnetic braking and enable the formation of persistent, rotationally supported, protostellar disks. In this paper, we first demonstrate that the classic microscopic resistivity is not large enough to enable disk formation by itself. We then experiment with a set of enhanced values for the resistivity in the range eta = 10(17) - 10(22) cm(2) s(-1). We find that a value of order 10(19) cm(2) s(-1) is needed to enable the formation of a 10(2) AU scale Keplerian disk; the value depends somewhat on the degree of core magnetization. The required resistivity is a few orders of magnitude larger than the classic microscopic values. Whether it can be achieved naturally during protostellar collapse remains to be determined.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据