Refractory carbon depletion by photolysis through dust collisions and vertical mixing
arXiv:2503.14597 · doi:10.1051/0004-6361/202553850
Abstract
The inner Solar System is depleted in refractory carbon in comparison to the interstellar medium and the depletion likely took place in the protoplanetary disk phase of the Solar System. We study the effect of photolysis of refractory carbon in the upper layers of the protosolar disk and its interplay with dust collisional growth and vertical mixing. We make use of a 1D Monte Carlo model to simulate dust coagulation and vertical mixing. To model the FUV flux of the disk, we use a simple analytical prescription and benchmark it with data from a radiative transfer simulation. We study the effects of fragmentation and bouncing on dust distribution and the propagation of carbon depletion. We find that when bouncing is included, the size distribution is truncated at smaller sizes than fragmentation-limited size distributions but there is a loss of small grains as well. The population of small grains is reduced due to fewer fragmentation events and this reduces the effectiveness of photolysis. We find that dust collisional growth and vertical mixing increase the effectiveness of carbon depletion by efficiently replenishing carbon to the upper regions of the disk with higher FUV flux. It takes around 100-300 kyr to reach the measured carbon abundances at 1 au, depending on the strength of the turbulence in the disk. These timescales are faster than reported by previous studies. Collisional redistribution and turbulent mixing are important aspects of dust evolution that should be included when modeling dust chemistry as they can influence the efficiency of chemical processes. Photolysis, along with another process such as sublimation, most likely played a key role in refractory carbon depletion that we see around us in the inner Solar System.
19 pages, 18 figures, accepted for publication in Astronomy & Astrophysics
References in corpus (19)
- Protoplanetary Disk Structures in Ophiuchus
- Particle Stirring in Turbulent Gas Disks: Including Orbital Oscillations
- Dust size distributions in coagulation/fragmentation equilibrium: Numerical solutions and analytical fits
- Dust coagulation in protoplanetary disks: porosity matters
- Bifurcation of planetary building blocks during Solar System formation
- Contemporary formation of early solar system planetesimals at two distinct radial locations
- A highly settled disk around Oph 163131
- Global MHD simulations of stratified and turbulent protoplanetary discs. II. Dust settling
- Destruction of Refractory Carbon in Protoplanetary Disks
- The spatial distribution of carbon dust in the early solar nebula and the carbon content of planetesimals
- Rapid Formation of Massive Planetary Cores in a Pressure Bump
- Photoevaporative Dispersal of Protoplanetary Disks around Evolving Intermediate-mass Stars
- Thermal Waves in Irradiated Protoplanetary Disks
- Chemical Feedbacks of Pebble Growth: Impacts on CO depletion and C/O ratios
- Destruction of refractory carbon grains drives the final stage of proto-planetary disk chemistry
- System-level fractionation of carbon from disk and planetesimal processing
- Carbon Depletion in the Early Solar System
- Rapid Formation of Exoplanetesimals Revealed by White Dwarfs
- Monte Carlo Simulation of Sugar Synthesis on Icy Dust Particles Intermittently Irradiated by UV in a Protoplanetary Disk