Reimagining the water snowline

Abstract

Water is a molecule that is tightly related to many facets of star and planet formation. Water's abundance and distribution, especially the location of it's snowline has thus been the subject of much study. While water is seen to be abundant in the inner region of proto-planetary disks in infrared spectroscopy, detections of water in the disk in the sub-millimeter are rare, with only one detection towards AS 205. Here we put the multitude of non-detections and the single detection into context of recent physico-chemical models. We find that the 321.2257 GHz (10(2,9) - 9(3,6)) line detection towards AS 205 is inconsistent with a normal inner disk temperature structure and that the observed line must be masing. Furthermore, the emitting area derived from the line width, together with published analyses on water in disks around T-Tauri stars implies that the water snowline in the disk surface is at the same location as the snowline in the mid-plane. We propose that this is caused by vertical mixing continuously sequestering water from the warm surface layers into the cold disk midplane.

arXiv commentAccepted for publication in ApJL, 6 pages, 3 figures

References in corpus (43)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Astropy: A Community Python Package for Astronomy
• The NumPy array: a structure for efficient numerical computation
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• A computer program for fast non-LTE analysis of interstellar line spectra
• The Disk Substructures at High Angular Resolution Project (DSHARP): I. Motivation, Sample, Calibration, and Overview
• The Evolution of the Water Distribution in a Viscous Protoplanetary Disk
• Exoplanetary Atmospheres: Key Insights, Challenges and Prospects
• Detection of the Water Reservoir in a Forming Planetary System
• A Spitzer survey of mid-infrared molecular emission from protoplanetary disks I: Detection rates
• Fossilized condensation lines in the Solar System protoplanetary disk
• A Spitzer Survey of Mid-Infrared Molecular Emission from Protoplanetary Disks II: Correlations and LTE Models
• Volatile carbon locking and release in protoplanetary disks. A study of TW Hya and HD 100546
• The structure and dynamics of molecular gas in planet-forming zones: A CRIRES spectro-astrometric survey
• Water in star-forming regions (WISH): Physics and chemistry from clouds to disks as probed by Herschel spectroscopy
• CO Depletion in Protoplanetary Disks: A Unified Picture Combining Physical Sequestration and Chemical Processing
• Radiative transfer models of mid-infrared H2O lines in the Planet-forming Region of Circumstellar Disks
• Organic Molecules and Water in the Inner Disks of T Tauri Stars
• Transport of CO in Protoplanetary Disks: Consequences of Pebble Formation, Settling, and Radial Drift
• CO rovibrational emission as a probe of inner disk structure
• Systematic Variations of CO Gas Abundance with Radius in Gas-rich Protoplanetary Disks
• Sensitive limits on the abundance of cold water vapor in the DM Tau protoplanetary disk
• Consistent dust and gas models for protoplanetary disks III. Models for selected objects from the FP7 DIANA project
• Spectrally resolved pure rotational lines of water in protoplanetary disks
• Tracing water vapor and ice during dust growth
• Volatile snowlines in embedded disks around low-mass protostars
• The Physics of Water Masers observable with ALMA and SOFIA: Model Predictions for Evolved Stars
• The depletion of water during dispersal of planet-forming disk regions
• Survey of cold water lines in protoplanetary disks: indications of systematic volatile depletion
• CO2 infrared emission as a diagnostic of planet-forming regions of disks
• Measurements of water surface snow lines in classical protoplanetary disks
• Ro-vibrational excitation of an organic molecule (HCN) in protoplanetary disks
• Water delivery by pebble accretion to rocky planets in habitable zones in evolving disks
• Candidate Water Vapor Lines to Locate the H${}_2$O Snowline through High-Dispersion Spectroscopic Observations I. The Case of a T Tauri Star
• Efficiency of radial transport of ices in protoplanetary disks probed with infrared observations: the case of CO${}_2$
• Dust continuum emission and the upper limit fluxes of sub-millimeter water lines of the protoplanetary disk around HD 163296 observed by ALMA
• Dependence of Biological Activity on the Surface Water Fraction of Planets
• A high resolution mid-infrared survey of water emission from protoplanetary disks
• Missing water in Class I protostellar disks
• Submillimeter Array Observations of 321 GHz Water Maser Emission in Cepheus A
• The chemistry of planet-forming regions is not interstellar
• Candidate Water Vapor Lines to Locate the ${\mathrm{H}}_2\mathrm{O}$ Snowline through High-dispersion Spectroscopic Observations. III. Submillimeter ${\mathrm{H}}_2$${}^{16}\mathrm{O}$ and ${\mathrm{H}}_2$${}^{18}\mathrm{O}$ Lines
• Spectrally Resolved Mid-Infrared Molecular Emission from Protoplanetary Disks and the Chemical Fingerprint of Planetesimal Formation

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• Resolved ALMA observations of water in the inner astronomical units of the HL Tau disk
• Water UV-Shielding in the Terrestrial Planet-Forming Zone: Implications for Oxygen-18 Isotope Anomalies in H2-18O Infrared Emission and Meteorites
• Zooming into the water snowline: high resolution water observations of the HL Tau disk
• Water UV-shielding in the terrestrial planet-forming zone: Implications from water emission