function n2t, p

; Return N2 temperature as a function of vapor pressure in microbar
a_liq  =[1.51050147e1, -6.15496072e2, -2.31314834e3, -5.89850934e4, 0.]
a_beta= [1.64302619e1, -6.50497257e2, -8.52432256e3,  1.55914234e5, -1.06368300e6]
a_alpha=[1.88550118e1, -8.57102332e2, -1.01891053e3,  1.28466570e4, -4.82177497e4]
a=a_beta
if p lt n2vp(35.62) then a=a_alpha
if p gt n2vp(63.152) then a=a_gamma
a[0] = a[0] - alog(p/1.33322e3)
roots = fz_roots(a)
gd = where( imaginary(roots) eq 0 and real_part(roots) gt 0, ngd)
t = 1/real_part(roots[gd[0]])
return, t
end