The ".krz" format

The "krz" format was developed as part of a project aimed at self-consistent determinations of abundances in pulsating early-type stars (B to F). This project was carried out at the Institute for Astronomy in Vienna and more details can be found in http://ams.astro.univie.ac.at/.
An explanation of the .krz format is given below.
Among other things the following issues have been addressed within this project:

• Creation of a complete database of atomic line data (VALD, http://www.astro.uu.se/~vald/ , Kupka et al.: 1999, A&AS 138, 119) used for opacity calculations and spectral synthesis;
• Calculation of model atmospheres consistent with the derived abundances (Piskunov & Kupka: 2001, ApJ 547, 1040);
• Fast and accurate spectral synthesis codes with and without the effects of magnetic fields like SME (Valenti & Piskunov: 1996, A&AS 118, 595) and SYNTHMAG (Piskunov: 1999, in Proc. of Solar polarization workshop, Bangalore, 1998, Nagendra & Stenflo (eds.), Kluwer Astrophysics and space science library, v. 243, p. 515);
• Doppler Imaging of chemical composition and magnetic fields (Piskunov & Kochukhov: 2002, A&A 381, 736).

All of the above requires a subset of data from a model atmosphere in a compact format like the KRZ. Since several of the programmes mentioned above are actively used in stellar astrophysics we offer an option to retrieve the MARCS models also in the KRZ format.
When you download models with SPHERICAL geometry in the .krz format, then

• the MODEL TYPE will be 3 ( for the plane-parallel models it is 0 (zero) )
• in the listing of the model there will be a sixth column containing the the radial distance from a reference layer (in cm), counted positive outwards of this layer and negative inwards. This reference layer is where the Rosseland optical depth equals 1 in the model (log tau_Ross = 0.0). The stellar radius (at log tau_Ross = 0.0) is given in the corresponding ".mod" format file.

Explanation of the "krz" model format. By Nikolai Piskunov 2010-06-10

        TITLE SDSC GRID  [+0.0]   VTURB 2.0 KM/S    L/H 1.25 UNSCALED

        T EFF= 7500. GRAV= 4.5  MODEL TYPE= 0 WLSTD= 5000.

        1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 0 0 0 0 0                         - OPACITY SWITCHES

         0.911  0.089 -10.88 -10.89  -9.44  -3.48  -3.99  -3.11  -7.48  -3.95

         -5.71  -4.46  -5.57  -4.49  -6.59  -4.83  -6.54  -5.48  -6.82  -5.68

         -8.94  -7.05  -8.04  -6.37  -6.65  -4.37  -7.12  -5.79  -7.83  -7.44

         -9.16  -8.63  -9.67  -8.69  -9.41  -8.81  -9.44  -9.14  -9.80  -9.54

        -10.62 -10.12 -20.00 -10.20 -10.92 -10.35 -11.10 -10.18 -10.58 -10.04

        -11.04  -9.80 -10.53  -9.81 -10.92  -9.91 -10.82 -10.49 -11.33 -10.54

        -20.00 -11.04 -11.53 -10.92 -11.94 -10.94 -11.78 -11.11 -12.04 -10.96

        -11.28 -11.16 -11.91 -10.93 -11.77 -10.59 -10.69 -10.24 -11.03 -10.95

        -11.14 -10.19 -11.33 -20.00 -20.00 -20.00 -20.00 -20.00 -20.00 -11.92

        -20.00 -12.51 -20.00 -20.00 -20.00 -20.00 -20.00 -20.00 -20.00 72

        1.494770850E-04,   4892.5, 7.94600E+09, 6.99057E+12, 1.50828E-11,

        1.983653960E-04,   4912.0, 9.81300E+09, 9.24075E+12, 1.99378E-11,

        2.605118600E-04,   4933.4, 1.21100E+10, 1.20835E+13, 2.60713E-11,

        3.383485310E-04,   4954.9, 1.48600E+10, 1.56274E+13, 3.37177E-11,

        4.346934090E-04,   4976.9, 1.81400E+10, 1.99941E+13, 4.31392E-11,

        5.527391110E-04,   4998.8, 2.20200E+10, 2.53075E+13, 5.46034E-11,

        6.962465410E-04,   5020.9, 2.65800E+10, 3.17412E+13, 6.84848E-11,

        8.694794060E-04,   5043.1, 3.19500E+10, 3.94671E+13, 8.51541E-11,

        1.077280610E-03,   5065.9, 3.82800E+10, 4.86771E+13, 1.05026E-10,

        1.325020170E-03,   5089.5, 4.57400E+10, 5.95877E+13, 1.28566E-10,

        1.618741570E-03,   5114.0, 5.45800E+10, 7.24517E+13, 1.56322E-10,

        1.965294820E-03,   5139.7, 6.50600E+10, 8.75249E+13, 1.88844E-10,

        ...
    

or

        TITLE MARCS 35 model for MLT convection testing. Vturb  2.0 km/s

        T EFF= 6500. GRAV= 2.0  MODEL TYPE= 3 WLSTD= 5000 SPHERICAL, RADIUS= 1.155E+12 cm

        1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 0 0 0 0 0 - OPACITY SWITCHES

         0.922  0.078 -10.88 -10.89  -9.44  -5.65  -6.26  -4.98  -7.48  -5.80

         -7.87  -6.11  -7.67  -6.13  -6.59  -6.50  -6.54  -5.48  -8.96  -7.33

        -10.87  -8.74 -10.04  -8.40  -8.65  -6.59  -9.12  -7.81  -7.83  -7.44

         -9.16  -8.63  -9.67  -8.69  -9.41  -8.81  -9.44  -9.14  -9.80  -9.54

        -10.62 -10.12 -20.00 -10.20 -10.92 -10.35 -11.10 -10.18 -10.58 -10.04

        -11.04  -9.80 -10.53  -9.81 -10.92  -9.91 -10.82 -10.49 -11.33 -10.54

        -20.00 -11.04 -11.53 -10.92 -11.94 -10.94 -11.78 -11.11 -12.04 -10.96

        -11.28 -11.16 -11.91 -10.93 -11.77 -10.59 -10.69 -10.24 -11.03 -10.95

        -11.14 -10.19 -11.33 -20.00 -20.00 -20.00 -20.00 -20.00 -20.00 -11.92

        -20.00 -12.51 -20.00 -20.00 -20.00 -20.00 -20.00 -20.00 -20.00 56

        4.754334316E-02,   4571.6, 1.64024E+09, 3.81952E+12, 7.94416E-12, 2.44799E+10,

        6.466705352E-02,   4613.0, 2.50945E+09, 6.46942E+12, 1.34563E-11, 2.27099E+10,

        8.941244334E-02,   4662.0, 3.81018E+09, 1.02419E+13, 2.13033E-11, 2.11329E+10,

        1.236606389E-01,   4714.4, 5.68486E+09, 1.53860E+13, 3.20032E-11, 1.97191E+10,

        1.695764661E-01,   4768.2, 8.31312E+09, 2.21840E+13, 4.61428E-11, 1.84345E+10,

        2.299538255E-01,   4821.7, 1.19096E+10, 3.10038E+13, 6.44878E-11, 1.72482E+10,

        3.084119260E-01,   4874.9, 1.67679E+10, 4.23195E+13, 8.80230E-11, 1.61355E+10,

        ...
    

• 1st line - header
• 2nd line
  • T_eff (K)
  • logg (cgs)
  • model type: 0 - plane-parallel, depth scale - column mass in g/cm²
  • model type: 1 - plane-parallel, depth scale - tau at std wavelength
  • model type: 2 - not used
  • model type: 3 - spherical, depth scale - column mass in g/cm²
  • model type: 4 - spherical, depth scale - tau at std wavelength
  • WLSTD - standard wavelength in Å (relevant for model type 1 and 4)
  • SPHERICAL - the same as model type 3 and 4
  • RADIUS - reference radius in cm
• 3rd line - continuous opacities used in calculations following Bob Kurucz convention
  1. - absorption by H
  2. - absorption by H₂⁺
  3. - absorption by H^-
  4. - Rayleigh scattering by H
  5. - absorption by He
  6. - absorption by He⁺
  7. - absorption by He^-
  8. - Rayleigh scattering by He
  9. - absorption by metals for cool stars (Si, Mg, Al, C, Fe)
  10. - absorption by metals for intermediate stars (N, O, Si⁺, Mg⁺, Ca⁺)
  11. - absorption by metals for hot stars (C, N, O, Ne, Mg, Si, S, Fe 1st to 4th ions)
  12. - Thomson scattering by electrons
  13. - Rayleigh scattering by H₂
  14. - 20. not used
• Lines 4-13 - normalized abundances for the first 99 elements in the periodic table: N_atom/N_all where N are number densities. The sum of all abundances is 1. Positive numbers are fractions while negative numbers are log₁₀ of fractions. The last number in line 13 is the number of depth layers in the model.
• Lines 14 and down are the model data. Plane-parallel models have 5 columns while spherical have 6.
  1. column: depth in column mass or optical depth at standard wavelength
  2. column: temperature in K
  3. column: number density of free electrons in cm^-3
  4. column: number density of all other particles (except electrons) in cm^-3
  5. column: density in g/cm³
  6. column: (spherical model only): height in cm relative to the reference radius given in the header