Astro & cosmo-chemical consequences of accretion bursts I: the D/H ratio of water

Abstract

The D/H ratio of water in protostellar systems is a result of both inheritance from the parent molecular cloud and isotopic exchange in the disc. A possibly widespread feature of disc evolution, ignored in previous studies, is accretion bursts (or FU Orionis outbursts), which may thermally process a large fraction of the water. One proposed underlying mechanism for FU Orionis outbursts relies on the presence of a magnetically dead zone. Here we examine the evolution of (D/H)${}_{\mathrm{water}}$ in 1D simulations of a disc's evolution that include dead zones and infall from an envelope with given D/H ratio in the infalling water ($\sim 10^{-3}$), and compare the results with similar calculations without dead zones. We find that the accretion bursts result in a significantly lower (D/H)${}_{\mathrm{water}}$ ratio and a more extended region (radius up to $\sim 1-3$ AU) where water is equilibrated with hydrogen gas (D/H=$2\times 10^{-5}$), when compared to burst-free models. Solar system constraints suggest that our solar nebula either experienced no accretion bursts and had a Schmidt number $\lesssim 0.2$ or had a Schmidt number closer to "nominal" values ($\sim 1$) and experienced several accretion bursts. Finally, future observations of (D/H)${}_{\mathrm{water}}$ in protoplanetary discs will allow inferences about angular momentum properties of the disc during disc building and the role of accretion bursts.

arXiv comment14 pages, 13 figures, accepted for publication in MNRAS

References in corpus (39)

• Spectral Energy Distributions of T Tauri Stars With Passive Circumstellar Disks
• The Spitzer c2d Legacy Results: Star Formation Rates and Efficiencies; Evolution and Lifetimes
• Dense Cores in Dark Clouds. XIV. N2H+(1-0) maps of dense cloud cores
• The locality of transport in self-gravitating accretion discs
• The Evolution of the Water Distribution in a Viscous Protoplanetary Disk
• Episodic accretion in magnetically layered protoplanetary discs
• Evolution of protoplanetary disks: Constraints from DM Tauri and GM Aurigae
• Local Magnetohydrodynamical Models of Layered Accretion Disks
• Detection of the Water Reservoir in a Forming Planetary System
• The chemical history of molecules in circumstellar disks. I. Ices
• Testing the locality of transport in self-gravitating accretion discs - II. The massive disc case
• Long-term Evolution of Protostellar and Protoplanetary Disks. II. Layered Accretion with Infall
• 2-D simulations of FU Orionis disk outbursts
• Modeling Magnetorotational Turbulence in Protoplanetary Disks with Dead Zones
• Long-term Evolution of Protostellar and Protoplanetary Disks. I. Outbursts
• The chemical history of molecules in circumstellar disks. II. Gas-phase species
• Herschel measurements of the D/H and 16O/18O ratios in water in the Oort-cloud comet C/2009 P1 (Garradd)
• Accretion in protoplanetary disks: the imprint of core properties
• Dust Transport in Protostellar Disks Through Turbulence and Settling
• Episodic Accretion in Young Stars
• Chemo-dynamical deuterium fractionation in the early solar nebula: The origin of water on Earth and in asteroids and comets
• The Gravo-Magneto Limit Cycle in Accretion Disks
• Crystalline silicates as a probe of disk formation history
• CO2 Ice toward Low-luminosity, Embedded Protostars: Evidence for Episodic Mass Accretion via Chemical History
• Water transport in protoplanetary disks and the hydrogen isotopic composition of chondrites
• Fundamental aspects of episodic accretion chemistry explored with single-point models
• Chemical Evolution in VeLLOs
• Variable Accretion Outbursts in Protostellar Evolution
• The effect of episodic accretion on the phase transition of CO and CO_2 in low-mass star formation
• Propagation of the Gravo-Magneto Disc Instability
• Accreting planets as dust dams in `transition' discs
• Hot water in the inner 100 AU of the Class 0 protostar NGC1333 IRAS2A
• The Mdot - M* relation of pre-main sequence stars: a consequence of X-ray driven disc evolution
• The Spitzer c2d Survey of Nearby Dense Cores XI : Infrared and Submillimeter Observations of CB130
• Snow-lines as probes of turbulent diffusion in protoplanetary discs
• Long-term Evolution of Photoevaporating Protoplanetary Disks
• Water in Comets 71P/Clark and C/2004 B1 (LINEAR) with Spitzer
• The gravo-magneto disc instability with a viscous dead zone
• Importance of thermal diffusion in the gravo-magnetic limit cycle

Cited by in corpus (10)

• Chemical tracers of episodic accretion in low-mass protostars
• How do stars gain their mass? A JCMT/SCUBA-2 Transient Survey of Protostars in Nearby Star Forming Regions
• Exploring the Origins of Deuterium Enrichments in Solar Nebular Organics
• JWST detections of amorphous and crystalline HDO ice toward massive protostars
• A "Rosetta Stone" for protoplanetary disks: The synergy of multi-wavelength observations
• Constraining the Chemical Signatures and the Outburst Mechanism of the Class 0 Protostar HOPS 383
• Pristine ices in a planet-forming disk revealed by heavy water
• Nebular dead zone effects on the D/H ratio in chondrites and comets
• Probing episodic accretion with chemistry: CALYPSO observations of IRAM 04191+1522. Results from the CALYPSO IRAM-PdBI survey
• Variable protostellar mass accretion rates in cloud cores