J/ApJS/224/9 Stand2015 Atmospheric Chemical Network for HCNO (Rimmer+, 2016)
A chemical kinetics network for lightning and life in planetary atmospheres.
Rimmer P.B., Helling C.
<Astrophys. J. Suppl. Ser., 224, 9 (2016)>
=2016ApJS..224....9R 2016ApJS..224....9R (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics ; References
Keywords: astrobiology; atmospheric effects; molecular processes;
planetary systems
Abstract:
There are many open questions about prebiotic chemistry in both
planetary and exoplanetary environments. The increasing number of
known exoplanets and other ultra-cool, substellar objects has
propelled the desire to detect life and prebiotic chemistry outside
the solar system. We present an ion-neutral chemical network
constructed from scratch, Stand2015, that treats hydrogen, nitrogen,
carbon, and oxygen chemistry accurately within a temperature range
between 100 and 30000K. Formation pathways for glycine and other
organic molecules are included. The network is complete up to
H6C2N2O3. Stand2015 is successfully tested against atmospheric
chemistry models for HD 209458b, Jupiter, and the present-day Earth
using a simple one-dimensional photochemistry/diffusion code. Our
results for the early Earth agree with those of Kasting for CO2,
H2, CO, and O2, but do not agree for water and atomic oxygen. We
use the network to simulate an experiment where varied chemical
initial conditions are irradiated by UV light. The result from our
simulation is that more glycine is produced when more ammonia and
methane is present. Very little glycine is produced in the absence of
any molecular nitrogen and oxygen. This suggests that the production
of glycine is inhibited if a gas is too strongly reducing. Possible
applications and limitations of the chemical kinetics network are also
discussed.
Description:
The STAND2015 gas-phase chemical network is an H/C/N/O network with
reactions involving He, Na, Mg, Si, Cl, Ar, K, Ti, and Fe, developed
from scratch. It contains all known reactions for species of up to six
hydrogen, two carbon, two nitrogen, and three oxygen atoms, for which
a rate constant has been published, as well as a less complete network
involving species with three or more carbon atoms, three nitrogen
atoms, and/or four oxygen atoms.
The photochemistry/diffusion code, ARGO (was developed based on NAHOON
(Wakelam et al. 2012ApJS..199...21W 2012ApJS..199...21W)), was used to test the network.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table4.dat 73 161 Neutral species included in the Stand2015 network
table6.dat 94 2980 Stand2015 chemical kinetics network
refs.dat 589 691 References
--------------------------------------------------------------------------------
See also:
J/ApJ/761/166 : Terrestrial exoplanet atmospheres. I. (Hu+, 2012)
J/ApJ/649/1043 : Transiting extrasolar planet HD 209458b (Richardson+, 2006)
J/A+AS/109/125 : Photoionisation cross section (Verner+, 1995)
http://kida.obs.u-bordeaux1.fr/ : Kinetic Database for Astrochemistry
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- New Network Formula
19- 35 A17 --- Std Standard Formula
37- 64 A28 --- Name Molecule identifier
66- 73 A8 --- Data Thermochem data source ("Burcat", "Benson" or
"NASA-CEA") (1)
--------------------------------------------------------------------------------
Note (1): The Burcat values for the NASA coefficients have been used for all
possible species. For some species, however, the coefficients had to
be obtained from other sources. For sources with elements Na, Mg, Si,
Cl, K, Ti, and Fe, the Burcat values were sparse, so we made use
instead of the NASA-CEA values (McBride et al. 1993cctt.rept.....M;
Gordon & McBride 1999, Thermodynamic Data to 20000 K for Monatomic
Gases (Cleveland: NASA)). For some species, the thermodynamic
properties have not been determined. In these cases, for neutral
species we use Benson's additivity method as described by
Cohen & Benson (1993, ChRv 93 2419).
See Appendix B.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Seq Index number
6- 7 A2 --- Type Type (1)
9- 66 A58 --- Reaction Reaction
68- 75 E8.2 --- alpha ? The α value (2)
77- 82 F6.2 --- beta [-19.7/12.4]? The β value
84- 89 I6 --- gamma [0/129000]? The γ value
90 A1 --- f_gamma Flag on gamma (3)
92- 94 A3 --- Ref Reference (see refs.dat file)
--------------------------------------------------------------------------------
Note (1): Type as follows:
2d = neutral species;
3i = ion-neutral species;
ti = ionization reaction;
2n = forward reaction;
2i = reversed reaction;
pi = photoionization reaction;
pd = photodissociation reaction;
cr = cosmic ray reaction;
dr = dissociative recombination reaction.
ra = radiative association reaction.
Note (2): For reactions involving one reactant, the units are s-1, when there
are two reactants, units are cm3/s, and when there are three
reactants, units are cm6/s. The reader should consult both the
reaction 'Type' and the number of reactants given in 'Reaction' to
determine the units.
Note (3):
* = Consult Section 2.3 on how the reaction barrier is calculated.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- Ref Reference code
5- 23 A19 --- BibCode Bibcode if any
25- 56 A32 --- Auth First author's name(s)
58-589 A532 --- Comm Comment
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 28-Jun-2016