program w

       implicit real*8 (a-h,o-z)

       print *
       print *, "  Densite? (cm-3)"
       read *, dens

       print *, "  Temperature? (K)"
       read *, temper

       w = w_hd(dens,temper)

       print *, "  Refroidissement HD:"
       print *, "    nH = ", dens, " cm-3, T = ", temper, " K"
       print *, "     W = ", w, " erg s-1"
       print *

       stop
       end

c---------------------------------------------------

       real*8 function w_hd(dens,temper)

       implicit real*8 (a-h,o-z)

       data aa, bb, omeg, phi, c1, c2, d1, d2 /
     1      -26.2982d0, -0.215807d0, 2.03657,
     2       4.63258d0, 0.283978, -1.27333,
     3      -2.08189, 4.66288 /

       y = log10(dens)
       x = log10(temper)

       w = 0.5d0 * y + aa * x**bb
     1   - sqrt( 0.25d0 * y*y
     2   + (c1*y+c2) * sin(omeg*x+phi) + (d1*y+d2) )

       w_hd = 10.0d0**w
       return
       end