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Title: Water vapor distribution in protoplanetary disks

Water vapor has been detected in protoplanetary disks. In this work, we model the distribution of water vapor in protoplanetary disks with a thermo-chemical code. For a set of parameterized disk models, we calculate the distribution of dust temperature and radiation field of the disk with a Monte Carlo method, and then solve the gas temperature distribution and chemical composition. The radiative transfer includes detailed treatment of scattering by atomic hydrogen and absorption by water of Lyα photons, since the Lyα line dominates the UV spectrum of accreting young stars. In a fiducial model, we find that warm water vapor with temperature around 300 K is mainly distributed in a small and well-confined region in the inner disk. The inner boundary of the warm water region is where the shielding of UV field due to dust and water itself become significant. The outer boundary is where the dust temperature drops below the water condensation temperature. A more luminous central star leads to a more extended distribution of warm water vapor, while dust growth and settling tends to reduce the amount of warm water vapor. Based on typical assumptions regarding the elemental oxygen abundance and the water chemistry, the column densitymore » of warm water vapor can be as high as 10{sup 22} cm{sup –2}. A small amount of hot water vapor with temperature higher than ∼300 K exists in a more extended region in the upper atmosphere of the disk. Cold water vapor with temperature lower than 100 K is distributed over the entire disk, produced by photodesorption of the water ice.« less
Authors:
;  [1]
  1. Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)
Publication Date:
OSTI Identifier:
22365255
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 792; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; ABUNDANCE; ATMOSPHERES; DISTRIBUTION; DUSTS; HOT WATER; HYDROGEN; ICE; LYMAN LINES; MONTE CARLO METHOD; OXYGEN; PROTOPLANETS; RADIANT HEAT TRANSFER; STARS; TEMPERATURE DISTRIBUTION; ULTRAVIOLET RADIATION; ULTRAVIOLET SPECTRA; WATER VAPOR