SIRIUS project. II. A new tree-direct hybrid code for smoothed particle hydrodynamics/N-body simulations of star clusters

被引:15
|
作者
Fujii, Michiko S. [1 ]
Saitoh, Takayuki R. [2 ,3 ]
Wang, Long [1 ]
Hirai, Yutaka [4 ,5 ]
机构
[1] Univ Tokyo, Grad Sch Sci, Dept Astron, Bunkyo Ku, 7-3-1 Hongo, Tokyo 1130033, Japan
[2] Kobe Univ, Grad Sch Sci, Dept Planetol, Nada Ku, 1-1 Rokkodai Cho, Kobe, Hyogo 6578501, Japan
[3] Tokyo Inst Technol, Earth Life Sci Inst, Meguro Ku, 2-12-1 Ookayama, Tokyo 1528551, Japan
[4] RIKEN, Ctr Computat Sci, Chuo Ku, 7-1-26 Minatojima Minami Machi, Kobe, Hyogo 6500047, Japan
[5] Tohoku Univ, Astron Inst, Aoba Ku, 6-3 Aramaki, Sendai, Miyagi 9808578, Japan
关键词
galaxies:star clusters: general; ISM: clouds; methods: numerical; open clusters and associations: general; stars: formation; SPECIAL-PURPOSE COMPUTER; INITIAL MASS FUNCTION; SIMD INSTRUCTION SET; 1ST-PRINCIPLE SIMULATIONS; HERMITE INTEGRATOR; STELLAR FEEDBACK; BROWN DWARF; EVOLUTION; ORIGIN; TIME;
D O I
10.1093/pasj/psab037
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Star clusters form via clustering star formation inside molecular clouds. In order to understand the dynamical evolution of star clusters in their early phase, in which they are still embedded in their surrounding gas, we need accurate integration of individual stellar orbits without gravitational softening in the systems including both gas and stars, as well as modeling of individual stars with a realistic mass function. We develop a new tree-direct hybrid smoothed particle hydrodynamics/N-body code, ASURA+BRIDGE, in which stars are integrated using a direct N-body scheme or PETAR, a particle-particle particle-tree scheme code, without gravitational softening. In ASURA+BRIDGE, stars are assumed to have masses randomly drawn from a given initial mass function. With this code, we perform star cluster formation simulations starting from molecular clouds without gravitational softening. We find that artificial dense cores in star cluster centers due to the softening disappear when we do not use softening. We further demonstrate that star clusters are built up via mergers of smaller clumps. The star clusters formed in our simulations include some dynamically formed binaries with minimum semi-major axes of a few au, and the binary fraction is higher for more massive stars.
引用
收藏
页码:1057 / 1073
页数:17
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