论文标题
从星系中超级质量黑洞周围的尘土谷物形成的“短晶石”
Formation of "Blanets" from Dust Grains around the Supermassive Black Holes in Galaxies
论文作者
论文摘要
在Wada，Tsukamoto和Kokubo（2019）中，我们首次提出，可以在银河系中心的超级质量黑洞（SMBH）周围形成新的行星“ Blanets”（即黑洞行星）。在这里，我们更详细地研究了雪线外（$ r_ {snow} \ sim $几个parsecs）外的尘埃凝血过程和物理状况，尤其是考虑到灰尘聚集体的径向对流的影响。我们发现，无量纲参数$α= v_t^2/c_s^2 $，其中$ v_t $是动荡的速度，$ c_s $是声音速度，描述湍流的粘度应小于0.04，以防止因核心造成的聚集而导致的磁盘，以防止collection毛破坏。 Blanets $τ_{gi} $的编队时间尺度$ r_ {snow} $是，$τ_{gi} \ simeq $ 70-80 Myr，$α= 0.01-0.04 $和$ m_和$ m_ {bh} = 10^6 m_ \ odot $。尺寸的质量从$ \ sim 20 m_e $到$ 3000 m_e $ in $ r <4 $ r <4 $ pc，$α= 0.02 $（$ m_e $是地球质量），与$ 4 m_e-6 m_e $相反，$ 4 m_e-6 m_e $对于没有辐射的顾问。我们的结果表明，\ textIt {blanets}可以围绕相对低的luminosity agns（$ l_ {bol} \ sim 10^{42} $ erg s $^{ - 1} $在他们的生命周期（$ \ simssim 10^8 $ yr）中形成。
In Wada, Tsukamoto, and Kokubo (2019), we proposed for the first time that a new class of planets, "blanets" (i.e., black hole planets), can be formed around supermassive black holes (SMBHs) in the galactic center. Here, we investigate the dust coagulation processes and physical conditions of the blanet formation outside the snow line ($r_{snow} \sim $ several parsecs) in more detail, especially considering the effect of the radial advection of the dust aggregates. We found that a dimensionless parameter $α= v_t^2/c_s^2$, where $v_t$ is the turbulent velocity and $c_s$ is the sound velocity, describing the turbulent viscosity should be smaller than 0.04 in the circumnuclear disk, to prevent the destruction of the aggregates due to collisions. The formation timescale of blanets $τ_{GI}$ at $r_{snow}$ is, $τ_{GI} \simeq$ 70-80 Myr for $α= 0.01-0.04$ and $M_{BH} = 10^6 M_\odot$. The mass of the blanets ranges from $\sim 20 M_E$ to $3000 M_E$ in $r < 4$ pc for $α= 0.02$ ($M_E$ is the Earth mass), which is in contrast with $ 4 M_E-6 M_E$ for the case without the radial advection. Our results suggest that \textit{blanets} could be formed around relatively low-luminosity AGNs ($L_{bol} \sim 10^{42}$ erg s$^{-1}$) during their lifetime ($\lesssim 10^8$ yr).
