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Detailed Model of the Growth of Fluffy Dust Aggregates in a Protoplanetary Disk: Effects of Nebular Conditions
- Source :
- The Astrophysical Journal. 897:182
- Publication Year :
- 2020
- Publisher :
- American Astronomical Society, 2020.
-
Abstract
- Coagulation of dust aggregates plays an important role in the formation of planets and is of key importance to the evolution of protoplanetary disks (PPDs). Characteristics of dust, such as the diversity of particle size, porosity, charge, and the manner in which dust couples to turbulent gas, affect the collision outcome and the rate of dust growth. Here we present a numerical model of the evolution of the dust population within a PPD which incorporates all of these effects. The probability that any two particles collide depends on the particle charge, cross-sectional area and their relative velocity. The actual collision outcome is determined by a detailed collision model which takes into account the aggregate morphology, trajectory, orientation, and electrostatic forces acting between charged grains. The data obtained in this research reveal the characteristics of dust populations in different environments at the end of the hit-and-stick growth, which establishes the foundation for the onset of the next growth stage where bouncing, mass transfer and fragmentation become important. For a given level of turbulence, neutral and weakly charged particles collide more frequently and grow faster than highly charged particles. However, highly charged particles grow to a larger size before reaching the bouncing barrier, and exhibit a "Runaway" growth, in which a few large particles grow quickly by accreting smaller particles while the rest of the population grows very slowly. In general, highly charged aggregates have a more compact structure and are comprised of larger monomers than neutral/weakly charged aggregates. The differences in the particle structure/composition not only affect the threshold velocities for bouncing and fragmentation, but also change the scattering and absorption opacity of dust, influencing the appearance of PPDs.
- Subjects :
- Earth and Planetary Astrophysics (astro-ph.EP)
Physics
education.field_of_study
010504 meteorology & atmospheric sciences
Opacity
Population
FOS: Physical sciences
Astronomy and Astrophysics
Protoplanetary disk
01 natural sciences
Charged particle
13. Climate action
Space and Planetary Science
Chemical physics
0103 physical sciences
Particle
Astrophysics::Earth and Planetary Astrophysics
Particle size
Protoplanet
education
010303 astronomy & astrophysics
Astrophysics - Earth and Planetary Astrophysics
0105 earth and related environmental sciences
Cosmic dust
Subjects
Details
- ISSN :
- 15384357
- Volume :
- 897
- Database :
- OpenAIRE
- Journal :
- The Astrophysical Journal
- Accession number :
- edsair.doi.dedup.....5c4933ee04862d026d76e2e896c7768b