St Andrews Research Repository

St Andrews University Home
View Item 
  •   St Andrews Research Repository
  • University of St Andrews Research
  • University of St Andrews Research
  • University of St Andrews Research
  • View Item
  •   St Andrews Research Repository
  • University of St Andrews Research
  • University of St Andrews Research
  • University of St Andrews Research
  • View Item
  •   St Andrews Research Repository
  • University of St Andrews Research
  • University of St Andrews Research
  • University of St Andrews Research
  • View Item
  • Login
JavaScript is disabled for your browser. Some features of this site may not work without it.

Uncertainties in water chemistry in disks : an application to TW Hydrae

Thumbnail
View/Open
Woitke_2013_AA_Uncertainties.pdf (3.957Mb)
Date
11/2013
Author
Kamp, I.
Thi, W. -F.
Meeus, G.
Woitke, P.
Pinte, C.
Meijerink, R.
Spaans, M.
Pascucci, I.
Aresu, G.
Dent, W. R. F.
Keywords
Astrochemistry
Protoplanetary disks
Stars: formation
Radiative transfer
Methods: numerical
Line: formation
Irradiated protoplanetary disks
Radiation thermochemical models
Fine-structure transitions
LY-alpha radiation
Rotational-exitation
X-ray
Interstellar-medium
Organic-molecules
Rate coefficients
Collisional excitation
QB Astronomy
QC Physics
Metadata
Show full item record
Altmetrics Handle Statistics
Altmetrics DOI Statistics
Abstract
Context. This paper discusses the sensitivity of water lines to chemical processes and radiative transfer for the protoplanetary disk around TW Hya. The study focuses on the Herschel spectral range in the context of new line detections with the PACS instrument from the Gas in Protoplanetary Systems project (GASPS). Aims. The paper presents an overview of the chemistry in the main water reservoirs in the disk around TW Hya. It discusses the limitations in the interpretation of observed water line fluxes. Methods. We use a previously published thermo-chemical Protoplanetary Disk Model (ProDiMo) of the disk around TW Hya and study a range of chemical modeling uncertainties: metallicity, C/O ratio, and reaction pathways and rates leading to the formation of water. We provide results for the simplified assumption of Tgas = Tdust to quantify uncertainties arising for the complex heating/cooling processes of the gas and elaborate on limitations due to water line radiative transfer. Results. We report new line detections of p-H2O (322-211) at 89.99 μm and CO J = 18-17 at 144.78 μm for the disk around TW Hya. Disk modeling shows that the far-IR fine structure lines ([O I], [C II]) and molecular submm lines are very robust to uncertainties in the chemistry, while the water line fluxes can change by factors of a few. The water lines are optically thick, sub-thermally excited and can couple to the background continuum radiation field. The low-excitation water lines are also sensitive to uncertainties in the collision rates, e. g. with neutral hydrogen. The gas temperature plays an important role for the [O I] fine structure line fluxes, the water line fluxes originating from the inner disk as well as the high excitation CO, CH+ and OH lines. Conclusions. Due to their sensitivity on chemical input data and radiative transfer, water lines have to be used cautiously for understanding details of the disk structure. Water lines covering a wide range of excitation energies provide access to the various gas phase water reservoirs (inside and outside the snow line) in protoplanetary disks and thus provide important information on where gas-phase water is potentially located. Experimental and/or theoretical collision rates for H2O with atomic hydrogen are needed to diminish uncertainties from water line radiative transfer.
Citation
Kamp , I , Thi , W -F , Meeus , G , Woitke , P , Pinte , C , Meijerink , R , Spaans , M , Pascucci , I , Aresu , G & Dent , W R F 2013 , ' Uncertainties in water chemistry in disks : an application to TW Hydrae ' , Astronomy & Astrophysics , vol. 559 , A24 . https://doi.org/10.1051/0004-6361/201220621
Publication
Astronomy & Astrophysics
Status
Peer reviewed
DOI
https://doi.org/10.1051/0004-6361/201220621
ISSN
0004-6361
Type
Journal article
Rights
© ESO, 2013. Reproduced with permission from Astronomy & Astrophysics, © ESO
Description
G.M. is supported by Ramon y Cajal grant RYC-2011-07920. I.K. acknowledges funding by an NWO MEERVOUD grant. W.F.T., P.W. and I.K. acknowledge funding from the EU FP7-2011 under Grant Agreement No. 284405. C.P. acknowledges funding from the European Commission’s 7th Framework Program (contract PERG06-GA-2009-256513) and from Agence Nationale pour la Recherche (ANR) of France under contract ANR-2010-JCJC-0504-01.
Collections
  • University of St Andrews Research
URI
http://hdl.handle.net/10023/5457

Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

Advanced Search

Browse

All of RepositoryCommunities & CollectionsBy Issue DateNamesTitlesSubjectsClassificationTypeFunderThis CollectionBy Issue DateNamesTitlesSubjectsClassificationTypeFunder

My Account

Login

Open Access

To find out how you can benefit from open access to research, see our library web pages and Open Access blog. For open access help contact: openaccess@st-andrews.ac.uk.

Accessibility

Read our Accessibility statement.

How to submit research papers

The full text of research papers can be submitted to the repository via Pure, the University's research information system. For help see our guide: How to deposit in Pure.

Electronic thesis deposit

Help with deposit.

Repository help

For repository help contact: Digital-Repository@st-andrews.ac.uk.

Give Feedback

Cookie policy

This site may use cookies. Please see Terms and Conditions.

Usage statistics

COUNTER-compliant statistics on downloads from the repository are available from the IRUS-UK Service. Contact us for information.

© University of St Andrews Library

University of St Andrews is a charity registered in Scotland, No SC013532.

  • Facebook
  • Twitter