c  Header fortran file with astronomical and physical constants definitions.
c  (cgs units).

      real*8 Pi,Yr,Myr,pc,M_Sun,CHI,mp,G,kpc,Gyr,boltz
c     #       ,rad

      parameter ( Pi = 3.141592653589793115997963468544185161591D+00 )
      parameter ( Yr = 3.15569253d+7 )
      parameter ( Myr = 3.15569253d+13 )
      parameter ( Gyr = 3.15569253d+16 )
      parameter ( pc = 3.085678d+18 )
      parameter ( kpc = 3.085678d+21 )
      parameter ( M_Sun = 1.9891d+33 )
      parameter ( boltz = 1.3806503d-16 )
c  Conversion factor "brightness temperature" -> "column density" (1/(cm^2*K*km/s))
      parameter ( CHI = 1.823d+18 )
      parameter ( mp = 1.672621d-24 )
      parameter ( G = 6.673d-8 )
c  Radian (in degrees):
c      parameter ( rad = 180.d0/pi )