Self-Sustained Recycling in the Inner Dust Ring of Pre-Transitional Disks

Abstract

Observations of pre-transitional disks show a narrow inner dust ring and a larger outer one. They are separated by a cavity with no or only little dust. We propose an efficient recycling mechanism for the inner dust ring which keeps it in a steady state. No major particle sources are needed for replenishment. Dust particles and pebbles drift outwards by radiation pressure and photophoresis. The pebbles grow during outward drift until they reach a balanced position where residual gravity compensates photophoresis. While still growing larger they reverse their motion and drift inward. Eventually, their speed is fast enough for them to be destroyed in collisions with other pebbles and drift outward again. We quantify the force balance and drift velocities for the disks LkCa15 and HD 135344B. We simulate single-particle evolution and show that this scenario is viable. Growth and drift timescales are on the same order and a steady state can be established in the inner dust ring.

Dust Density Distribution and Imaging Analysis of Different Ice Lines in Protoplanetary Disks

“…Kretke & Lin 2007;Regály et al 2012;Flock et al 2015;, secular gravitational instability (e.g. Youdin 2011;Takahashi & Inutsuka 2014), instabilities originating from dust settling (Lorén-Aguilar & Bate 2015), self-sustained recycling of inner dust rings (Husmann et al 2016), particle growth by condensation near ice lines (Saito & Sirono 2011;Ros & Johansen 2013;Stammler et al 2017), sintering of dust particles that inhibits dust growth near the ice lines (Okuzumi et al 2016), and planet-disk interaction (e.g. Rice et al 2006;Zhu et al 2011;Gonzalez et al 2012;Pinilla et al 2012b;Dipierro et al 2016;Dong & Fung 2016;Rosotti et al 2016).…”

“…The current literature for explaining dust rings and gaps in protoplanetary disks is very rich and includes zonal flows from the magnetorotational instability (MRI; e.g., Johansen et al 2009;Uribe et al 2011;Dittrich et al 2013;Simon & Armitage 2014), spatial variations of the disk viscosity (e.g., Kretke & Lin 2007;Regály et al 2012;Flock et al 2015;Pinilla et al 2016), secular gravitational instability (e.g., Youdin 2011; Takahashi & Inutsuka 2014), instabilities originating from dust settling (Lorén-Aguilar & Bate 2015), self-sustained recycling of inner dust rings (Husmann et al 2016), particle growth by condensation near ice lines (Saito & Sirono 2011;Ros & Johansen 2013;Stammler et al 2017), sintering of dust particles that inhibits dust growth near the ice lines (Okuzumi et al 2016), and planet-disk interaction (e.g., Rice et al 2006;Zhu et al 2011;Gonzalez et al 2012;Pinilla et al 2012a;Dipierro et al 2016;Dong & Fung 2016;Rosotti et al 2016). Although the latter explanation is the most widely used to interpret current observations, it is not a unique possibility, and several of the listed processes can play an important role during the disk evolution.…”

Selective Aggregation Experiments on Planetesimal Formation and Mercury-Like Planets

“…Larger bodies get more sensitive to turbulence and radial drift velocities increase. Taken together they move with higher velocity through the disk [51][52][53]. If they collide among themselves they tend to get destroyed easily as has also been seen in experiments [54][55][56].…”

Gas-induced friction and diffusion of rigid rotors

“…Our results are directly applicable to recent experiments with nonspherical levitated objects in high vacuum [11,15,[39][40][41][42][43]. Beyond optomechanics, the here derived equations may be relevant for explaining planet formation in interstellar dust [3,4], the interplanetary trajectory of elongated asteroids [44,45], and dusty plasma dynamics [46]. This paper is structured as follows: In Sec.…”

“…A particle moving and revolving in a rarefied gas experiences a nonconservative force and torque [1] due to its random collisions with the surrounding gas atoms [2]. The resulting dynamics proved relevant for phenomena as diverse as the size distribution of dust grains in protoplanetary disks [3,4], the motion of satellites in the outermost layer of the atmosphere [5][6][7], or the drag on dust particles in dirty plasmas [8]. However, only recent experiments [9][10][11] in the field of levitated optomechanics [12,13] are capable of resolving the stochastic effect of individual scattering events.…”