Thermal diffusivity for gas

The thermal diffusivity is the thermal conductivity divided by density $\rho$ and specific heat capacity at constant pressure $c_p$. It measures the ability of a material to conduct thermal energy relative to its ability to store thermal energy, and is approximately analogous to whether a material is "cold to the touch".

The sources are:

Symbol
$\alpha_{gas}$
Unit
m$^2$/s
Formulae
$1.847185729{\cdot}{10}^{-5}+1.161914598{\cdot}{10}^{-7} \theta_{gas}+2.373056947{\cdot}{10}^{-10} {\theta_{gas}}^2-5.769352751{\cdot}{10}^{-12} {\theta_{gas}}^3-6.369279936{\cdot}{10}^{-14} {\theta_{gas}}^4$humid air @ 1 atm (Tsilingiris2007)
$9.1018{\cdot}{10}^{-11} {T_{gas}}^2+8.8197{\cdot}{10}^{-8} T_{gas}-1.0654{\cdot}{10}^{-5}$air @ 1 atm (Dumas&Trancossi2009)
${10}^{-6}\left(-4.3274+4.119{\cdot}{10}^{-2} T_{gas}+1.5556{\cdot}{10}^{-4} {T_{gas}}^2\right)$air @ 1 atm (UW/MHTL 8406, 1984)
$\frac{k_{gas}}{\rho_{gas} c_{p,gas}}$general formula for gases
Related
$k_{gas}$
$\rho_{gas}$
Gas density [kg/m$^3$]
$\theta_{gas}$