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J/A+A/502/845       Dust coagulation in molecular clouds      (Ormel+, 2009)

Dust coagulation and fragmentation in molecular clouds: I. How collisions between dust aggregates alter the dust size distribution. Ormel C.W., Paszun D., Dominik C., Tielens A.G.G.M. <Astron. Astrophys. 502, 845 (2009)> =2009A&A...502..845O
ADC_Keywords: Molecular clouds ; Interstellar medium ; Models Keywords: ISM: dust, extinction - ISM: clouds - turbulence - methods: numerical Abstract: The cores in molecular clouds are the densest and coldest regions of the interstellar medium (ISM). In these regions ISM-dust grains have the potential to coagulate. This study investigates the collisional evolution of the dust population by combining two models: a binary model that simulates the collision between two aggregates and a coagulation model that computes the dust size distribution with time. In the first, results from a parameter study quantify the outcome of the collision - sticking, fragmentation (shattering, breakage, and erosion) - and the effects on the internal structure of the particles in tabular format. These tables are then used as input for the dust evolution model, which is applied to an homogeneous and static cloud of temperature 10K and gas densities between 103 and 107cm-3. Description: Quantities (Q) provided in the tables are (see Table 1 of the paper): Q=fmiss fraction of missing collisions Q=Nfk number of fragments in the large component Q=Sf standard deviation in Nf Q=fpwl fraction of mass in the power-law component Q=q slope in the power-law component Q=Cphi change in the filling factor of the large particle component These output quantities are sampled as function of 1. Recipe type: 'Global' or 'Local' 2. Normalized impact parameter 3. Dimensionless energy parameter eps, which is the collision energy divided by a critical energy threshold 4. The initial filling factor of the aggregate (phi) OR, in case of Q=fmiss, the ratio of the outer over the geometrical radius (Ra). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file recip1.dat 85 90 Collision recipe data for 4 ratio of the outer over the geometrical radius (Ra=aout/asigma) recip2.dat 90 450 Collision recipe data for 4 initial filling factor of the aggregate (phi)
Byte-by-byte Description of file: recip1.dat
Bytes Format Units Label Explanations
1- 7 A7 --- Recipe Recipe (GLOBAL or LOCAL) 8- 12 F5.3 --- b Normalized impact parameter (b/b_max) 14- 18 A5 --- Q [fmiss] Parameter name (G1) 20- 29 E10.4 ---- eps Dimensionless energy value (G2) 31- 36 F6.4 --- Ra1 First ratio of the outer over the geometrical radius value 38- 43 F6.4 --- Q1 Value of quantity Q at Ra=Ra1 45- 50 F6.4 --- Ra2 Second ratio of the outer over the geometrical radius value 52- 57 F6.4 --- Q2 Value of quantity Q at Ra=Ra2 59- 64 F6.4 --- Ra3 Third ratio of the outer over the geometrical radius value 66- 71 F6.4 --- Q3 Value of quantity Q at Ra=Ra3 73- 78 F6.4 --- Ra4 Fourth ratio of the outer over the geometrical radius value 80- 85 F6.4 --- Q4 Value of quantity Q at Ra=Ra4
Byte-by-byte Description of file: recip2.dat
Bytes Format Units Label Explanations
1- 7 A7 --- Recipe Recipe (GLOBAL or LOCAL) 8- 12 F5.3 --- b Normalized impact parameter (b/b_max) 14- 17 A4 --- Q Q parameter designation (G1) 19- 28 E10.4 ---- eps Dimensionless energy value (G2) 30- 35 F6.4 --- phi1 First different initial filling factor value 37- 43 F7.4 --- Q1 Value of quantity Q at phi=phi1 45- 50 F6.4 --- phi2 Second different initial filling factor value 52- 59 F8.4 --- Q2 Value of quantity Q at phi=phi2 61- 66 F6.4 --- phi3 Third different initial filling factor value 68- 75 F8.4 --- Q3 Value of quantity Q at phi=phi3 77- 82 F6.4 --- phi4 Fourth different initial filling factor value 84- 90 F7.4 --- Q4 Value of quantity Q at phi=phi4
Global notes: Note (G1): Quantities studied are: fmiss = fraction of missing collisions Nf = number of fragments in the large component Sf = standard deviation in Nf fpwl = fraction of mass in the power-law component, normalized to Ntot (global recipe) or Nµ (local recipe) q = slope in the power-law component Cphi = change in the filling factor of the large particle component Note (G2): Dimensionless energy parameter. This is the collision energy E=(1/2)µ.v2 divided by a critical energy Ecrit. See Equation (13) and Table 1 in the paper for its definition.
Acknowledgements: Chris W. Ormel, ormel(at)mpia-hd.mpg.de
(End) C.W. Ormel [MPIA], Patricia Vannier [CDS] 18-Jun-2009
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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