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Time-dependent CO depletion during the formation of protoplanetary disks

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningfagfællebedømt

  • C. Brinch
  • R. J. Van Weeren
  • M. R. Hogerheijde

Context. Understanding the gas abundance distribution is essential when tracing star formation using molecular line observations. Variations in density and temperature conditions can cause gas to freeze-out onto dust grains, and this needs to be taken into account when modeling a collapsing molecular cloud.Aims. This study aims to provide a realistic estimate of the CO abundance distribution throughout the collapse of a molecular cloud. We derive abundance profiles and synthetic spectral lines that can be compared with observations.Methods. We use a two-dimensional hydrodynamical simulation of a collapsing cloud and subsequent formation of a protoplanetary disk as input to the chemical calculations. From the resulting abundances, synthetic spectra are calculated using a molecular excitation and radiation transfer code.Results. We compare three different methods to calculate the abundance of CO. Our models also consider cosmic ray desorption and the effects of an increased CO binding energy. The resulting abundance profiles are compared with observations from the literature and are found to agree well.Conclusions. The resulting abundance profiles agree well with analytic approximations, and the corresponding line fluxes match the observational data. Our method to calculate abundances in hydrodynamical simulations should help comparisons with observations, and can easily be generalized to include gas-phase reaction networks.

OriginalsprogEngelsk
TidsskriftAstronomy & Astrophysics
Vol/bind489
Udgave nummer2
Sider (fra-til)617-625
Antal sider9
ISSN0004-6361
DOI
StatusUdgivet - okt. 2008
Eksternt udgivetJa

    Forskningsområder

  • Astrochemistry, Hydrodynamics, ISM: clouds, ISM: molecules, Stars: formation

ID: 142072543