Changing disc compositions via internal photoevaporation II: M dwarf systems

Abstract

The chemical evolution of the inner regions of protoplanetary discs is a complex process. Several factors influence it, one being the inward drift and evaporation of volatile-rich pebbles. During the disc's evolution, its inner part is first enriched with evaporating water-ice, resulting in a low C/O ratio. Afterwards, C-rich gas from the outer disc is transported inwards. Consequently, the C/O ratio of the inner disc increases again after 2 Myr. Previously, we studied how internal photoevaporation influences these processes in discs around Sun-like stars. We now extend our study to lower-mass stars, where the time evolution of the disc's C/O ratio is different due to the closer-in position of the evaporation fronts and differences in disc mass, size and structure. Our simulations are carried out with the semi-analytical 1D disc model chemcomp, which includes viscous evolution and heating, pebble growth and drift, pebble evaporation and condensation, as well as a simple chemical partitioning model. We show that internal photoevaporation plays a major role in the evolution of protoplanetary discs: As for Sun-like stars, photoevaporation opens a gap, which stops inward drifting pebbles. In addition, volatile-rich gas from the outer disc is carried away by the photoevaporative winds. Consequently, the C/O ratio in the inner disc remains low, contradicting observations of discs around low-mass stars. Our model implies that young inner discs (< 2 Myr) should be O-rich and C-poor, while older discs (> 2 Myr) should be C-rich. The survival of discs to this age can be attributed to lower photoevaporation rates, which either originate from a large spread of observed X-ray luminosities or from the photoevaporation model used here, which likely overestimates the photoevaporation efficiency. A reduction of the latter brings the calculated elemental abundances into better agreement with observations.

References in corpus (68)

• The chemical composition of the Sun
• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• The effects of snowlines on C/O in planetary atmospheres
• Towards a Deterministic Model of Planetary Formation I: a Desert in the Mass and Semi Major Axis Distributions of Extra Solar Planets
• Rapid growth of gas-giant cores by pebble accretion
• A simple model for the evolution of the dust population in protoplanetary disks
• Coagulation, fragmentation and radial motion of solid particles in protoplanetary disks
• Discovery of a planetary-mass companion within the gap of the transition disk around PDS 70
• The effect of gas drag on the growth of protoplanets -- Analytical expressions for the accretion of small bodies in laminar disks
• Separating gas-giant and ice-giant planets by halting pebble accretion
• Timescale of Mass Accretion in Pre-Main-Sequence Stars
• The imprint of exoplanet formation history on observable present-day spectra of hot Jupiters
• The Disk Substructures at High Angular Resolution Project (DSHARP) VI: Dust trapping in thin-ringed protoplanetary disks
• Gaps, Rings, and Non-Axisymmetric Structures in Protoplanetary Disks - From Simulations to ALMA Observations
• Trapping dust particles in the outer regions of protoplanetary disks
• The XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST)
• The stickiness of micrometer-sized water-ice particles
• On the theory of disc photoevaporation
• Pebble isolation mass --- scaling law and implications for the formation of super-Earths and gas giants
• Orbital and atmospheric characterization of the planet within the gap of the PDS 70 transition disk
• Formation of planetary systems by pebble accretion and migration: How the radial pebble flux determines a terrestrial-planet or super-Earth growth mode
• Chemical enrichment of giant planets and discs due to pebble drift
• Retrieving scattering clouds and disequilibrium chemistry in the atmosphere of HR 8799e
• Material enhancement in protoplanetary nebulae by particle drift through evaporation fronts
• Dust flow in gas disks in the presence of embedded planets
• The New Generation Planetary Population Synthesis (NGPPS). I. Bern global model of planet formation and evolution, model tests, and emerging planetary systems
• A solar C/O and sub-solar metallicity in a hot Jupiter atmosphere
• Formation of planetary systems by pebble accretion and migration: Growth of gas giants
• X-ray irradiated protoplanetary disk atmospheres II: Predictions from models in hydrostatic equilibrium
• How drifting and evaporating pebbles shape giant planets I: Heavy element content and atmospheric C/O
• Evidence for Disk Photoevaporation Driven by the Central Star
• Structure and kinematics of the Taurus star-forming region from Gaia-DR2 and VLBI astrometry
• The dispersal of protoplanetary discs I: A new generation of X-ray photoevaporation models
• Scaling Relations Associated with Millimeter Continuum Sizes in Protoplanetary Disks
• Metallicity, planet formation, and disc lifetimes
• Super-Earth masses sculpted by pebble isolation around stars of different masses
• How much does turbulence change the pebble isolation mass for planet formation?
• Mass-radius relationships for irradiated ocean planets
• Where is the Water? Jupiter-like C/H ratio but strong H${}_2$O depletion found on $\tau$ Boötis b using SPIRou
• MINDS. The detection of ${}^{13}$CO${}_2$ with JWST-MIRI indicates abundant CO${}_2$ in a protoplanetary disk
• Planet population synthesis driven by pebble accretion in cluster environments
• Characterizing the variable dust permeability of planet-induced gaps
• Planetary population synthesis
• How drifting and evaporating pebbles shape giant planets II: Volatiles and refractories in atmospheres
• Influence of sub- and super-solar metallicities on the compositions of solid planetary building blocks
• The Solar Nebula on Fire: A Solution to the Carbon Deficit in the Inner Solar System
• Abundant hydrocarbons in the disk around a very-low-mass star
• The dispersal of protoplanetary discs. II: Photoevaporation models with observationally derived irradiating spectra
• MINDS. Abundant water and varying C/O across the disk of Sz 98 as seen by JWST/MIRI
• The spatial distribution of carbon dust in the early solar nebula and the carbon content of planetesimals
• Close-in ice lines and the super-stellar C/O ratio in discs around very low-mass stars
• Dry or water world? How the water contents of inner sub-Neptunes constrain giant planet formation and the location of the water ice line
• Exploring the conditions for forming cold gas giants through planetesimal accretion
• Characterising thermal sweeping: a rapid disc dispersal mechanism
• MINDS. Hydrocarbons detected by JWST/MIRI in the inner disk of Sz28 consistent with a high C/O gas-phase chemistry
• The role of planetesimal fragmentation on giant planet formation
• How drifting and evaporating pebbles shape giant planets III: The formation of WASP-77A b and $\tau$ Boötis b
• Mind the gap: Distinguishing disc substructures and their impact on the inner disc composition
• BOWIE-ALIGN: How formation and migration histories of giant planets impact atmospheric compositions
• Photoevaporation of protoplanetary discs with PLUTO+PRIZMO I. Lower X-ray-driven mass-loss rates due to enhanced cooling
• Chemical evolution in ices on drifting, planet-forming pebbles
• Forming super-Mercuries: The role of stellar abundances
• Hydrocarbon chemistry in inner regions of planet forming disks
• Burned to ashes: How the thermal decomposition of refractory organics in the inner protoplanetary disc impacts the gas-phase C/O ratio
• Changing disc compositions via internal photoevaporation I: Solar-mass stars
• TriPoD: Tri-Population size distributions for Dust evolution. Coagulation in vertically integrated hydrodynamic simulations of protoplanetary disks
• Dust evolution by chemisputtering during protostellar formation
• Tracking the Chemical Evolution of Hydrocarbons Through Carbon Grain Supply in Protoplanetary Disks

Cited by in corpus (4)

• Chemical transformation of CO in evolving protoplanetary discs across stellar masses: a route to C-rich inner regions
• MINDS. Strong oxygen depletion in the inner regions of a very low-mass star disk?
• Timescales diagnostics for saving viscous and MHD-driven dusty discs from external photoevaporation
• Icy Volatile Enhancements in Evolving Protoplanetary Disks