THE FATE OF FALLBACK MATTER AROUND NEWLY BORN COMPACT OBJECTS
THE FATE OF FALLBACK MATTER AROUND NEWLY BORN COMPACT OBJECTS
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DOI：
10.1088/0004-637x/781/2/119
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发表时间：
2013-12
期刊：
影响因子：
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通讯作者：
R. Perna;P. Duffell;M. Cantiello;A. MacFadyen
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文献类型：
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作者：
R. Perna;P. Duffell;M. Cantiello;A. MacFadyen
多年来，围绕年轻中子星(NSS)的后退盘的存在被用来解释各种各样的现象。在这里，我们对超新星(SN)爆炸期间这种圆盘的形成进行了数值研究，考虑了超新星和黑洞(BH)的残留物。使用公共程序MESA，我们计算了Pre-SN物质的角动量分布，对于初始质量M在13-40M☉范围内的恒星，初始表面自转速度Vsurf在临界速度的25%到75%之间，对于金属丰度Z是太阳值的1%，10%和100%。对这些Pre-SN模型进行了能量E在1050-3×1052erg之间变化的爆炸，并计算了后备材料的数量。我们发现，如果磁矩在角动量输运中起着重要作用，那么NSS周围的后退盘，即使是低金属丰度的主序星，也不是SN爆炸的结果。只有在可以忽略的磁矩和微调的爆炸能量的条件下，才能在年轻的NSS周围形成这样的圆盘。对于那些留下BH残留物的恒星，如果磁场不起很大的作用，盘的形成是无处不在的；然而，与NS情况不同的是，即使在内部有强烈的磁耦合，盘也可以在Z，M，Vsurf，E参数空间的大范围内形成。结合文献中广泛讨论的紧凑、高吸积的后备磁盘，我们确定了上述参数空间中导致BHS周围延长、长寿命磁盘的区域。我们发现，这些盘中的物理条件可能有利于行星的形成，从而可能导致围绕BHS运行的行星的存在。
The presence of fallback disks around young neutron stars (NSs) has been invoked over the years to explain a large variety of phenomena. Here we perform a numerical investigation of the formation of such disks during a supernova (SN) explosion, considering both NS and black hole (BH) remnants. Using the public code MESA, we compute the angular momentum distribution of the pre-SN material, for stars with initial masses M in the range 13–40 M☉, initial surface rotational velocities vsurf between 25% and 75% of the critical velocity, and for metallicities Z of 1%, 10%, and 100% of the solar value. These pre-SN models are exploded with energies E varying between 1050–3 × 1052 erg, and the amount of fallback material is computed. We find that, if magnetic torques play an important role in angular momentum transport, then fallback disks around NSs, even for low-metallicity main-sequence stars, are not an outcome of SN explosions. Formation of such disks around young NSs can only happen under the condition of negligible magnetic torques and a fine-tuned explosion energy. For those stars that leave behind BH remnants, disk formation is ubiquitous if magnetic fields do not play a strong role; however, unlike the NS case, even with strong magnetic coupling in the interior, a disk can form in a large region of the Z, M, vsurf, E parameter space. Together with the compact, hyperaccreting fallback disks widely discussed in the literature, we identify regions in the above parameter space that lead to extended, long-lived disks around BHs. We find that the physical conditions in these disks may be conducive to planet formation, hence leading to the possible existence of planets orbiting BHs.