Access to Astronomical Catalogues

J/A+A/545/A12     Chemistry of IRC+10216 inner wind modelled  (Cherchneff, 2012)
The inner wind of IRC+10216 revisited: new exotic chemistry and diagnostic for
dust condensation in carbon stars.
    Cherchneff I.
   <Astron. Astrophys. 545, A12 (2012)>
   =2012A&A...545A..12C
ADC_Keywords: Stars, carbon ; Models, evolutionary

Keywords: astrochemistry - stars: carbon - stars: AGB and post-AGB -
          molecular processes

Abstract:
    We model the chemistry of the inner wind of the carbon star IRC+10216
    and consider the effects of periodic shocks induced by the stellar
    pulsation on the gas to follow the non-equilibrium chemistry in the
    shocked gas layers. We consider a very complete set of chemical
    families, including hydrocarbons and aromatics, hydrides, halogens,
    and phosphorous-bearing species. Our derived abundances are compared
    to those for the latest observational data from large surveys and the
    Herschel telescope.

    A semi-analytical formalism based on parameterised fluid equations is
    used to describe the gas density, velocity, and temperature from 1R
    to 5R. The chemistry is described using a chemical kinetic network
    of reactions and a set of stiff, ordinary, coupled differential
    equations is solved.

Description:
    The following table gives the rates by the Arrhenius expression
    k=A*(T/300)n*exp(-Ea/T)
    with A in s-1, cm3/s or cm6/s depending on the type of process,
    bimolecular, trimolecular, and unimolecular processes, respectively.
Objects:
    ----------------------------------------------------------
       RA   (2000)   DE      Designation(s)
    ----------------------------------------------------------
    09 47 57.2   +13 16 44   IRC +10216 = CW Leo
    ----------------------------------------------------------

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
tablea1.dat      123      378   The chemical reaction network ordered by
                                 type of reactions


See also:
    J/A+A/330/676 : IRC+10216 Silicon and sulfur chemistry (Willacy+ 1998)


Byte-by-byte Description of file: tablea1.dat

   Bytes Format Units   Label     Explanations

       1  A1    ---     Code      [ABCD] Code for type of reaction (1)
   3-  7  A5    ---     Num       Reaction number (1)
   9- 25  A17   ---     React     Reactants
  27- 28  A2    ---     ---       [->]
  32- 47  A16   ---     Prod      Products
  52- 59  E8.3  ---     A         A coefficient (in s-1, cm3/s or cm6/s
                                   depending on the type of process)
  63- 68  F6.2  ---     n         n factor
  72- 78  F7.1  K       Ea        Activation energy Ea in Kelvin
  81-123  A43   ---     Ref       References for the rate data (2)

Note (1): The chemical reaction network is sub-divided in three
     categories of processes as follows:
  A = termolecular (reaction labelled 3B for 3-body)
  B = collisional/thermal fragmentation (reaction labelled TF 
      for thermal fragmentation)
  C = neutral-neutral (reaction labelled NN)
  D = radiative association (reaction labelled RA)
Note (2): References as follows:
     E  = estimated rate
   NIST = National Institute of Standards and Technology Chemical Kinetics
          Database
 UDFA06 = UMIST database for Astrochemistry 2006
      1 = Andreazza & Singh (1997MNRAS.287..287A)
      2 = Andreazza & Marinho (2005ApJ...624.1121A)
      3 = Andreazza et al. (2006MNRAS.372.1653A)
      4 = Andreazza & Marinho (2007MNRAS.380..365A)
      5 = Andreazza et al. (2009MNRAS.400.1892A)
      6 = Appleton, Steinberg & Liquornik (1970, J. Chem. Phys., 52, 2205)
      7 = Babb & Dalgarno (1995, Phys. Review A 51, 3021)
      8 = Cherchneff & Dwek (2010ApJ...713....1C)
      9 = Giesen, Herzler & Roth (2003, J. Phys. Chem. A, 107, 5202)
     10 = Hanson (1973, J. Chem. Phys., 60, 4970)
     11 = Kruse & Roth (1997, J. Phys. Chem. A, 101, 2138)
     12 = Miller & Melius (1992, Combustion & Flame 91, 21)
     13 = Richter & Howard (2000, Prog. En. Comb. Science 26, 565)
     14 = Self & Plane (2003, Phys. Chem. Chem. Phys., 5, 1407)
     15 = Singh & Andreazza (2000ApJ...537..261S)
     16 = Wakelam et al. (2009A&A...495..513W)
     17 = Andreazza et al. (1995ApJ...451..889A)
     18 = Scherer (2000, Proceedings of the Combustion Institute 25, 1511)
     19 = Woon & Herbst (1996ApJ...465..795W)
     20 = Baulch (1992, J. Phys. Chem. Ref. Data 21, 411)
     21 = Kumaran (1994, J. Chem. Phys. 101, 9487)


Acknowledgements:
    Isabelle Cherchneff, isabelle.cherchneff(@)unibas.ch
(End)                                        Patricia Vannier [CDS]  09-Aug-2012