Formation of “Blanets” from Dust Grains around the Supermassive Black Holes in Galaxies
Keiichi Wada, Yusuke Tsukamoto, Eiichiro Kokubo
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 snowline (rsnow∼ several parsecs) in more detail, especially considering the effect of the radial advection of the dust aggregates. We found that the viscous α-parameter in the turbulent circumnuclear disk should be smaller than 0.04, to prevent the destruction of the aggregates due to collisions. The formation timescale of blanets τGI at rsnow is, τGI≃ 70-80 Myr for α=0.01−0.04 and MBH=106M⊙. The mass of the blanets ranges from ∼20ME to 3000ME in r<4 pc for α=0.02 (ME is the Earth mass), which is in contrast with 4ME−6ME for the case without the radial advection. Our results suggest that \textit{blanets} could be formed around relatively low-luminosity AGNs (Lbol∼1042 erg s−1) during their lifetime (≲108 yr).
Comments: 16 pages, 7 figures, submitted to ApJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2007.15198 [astro-ph.EP] (or arXiv:2007.15198v1 [astro-ph.EP] for this version)
Submission history
From: Keiichi Wada
[v1] Thu, 30 Jul 2020 03:00:58 UTC (434 KB)
