Observationally measuring the location of the \mathrm { H _ { 2 } O } snowline is crucial for understanding the planetesimal and planet formation processes , and the origin of water on Earth .
In disks around Herbig Ae stars ( T _ { \mathrm { * } } \sim 10,000K ,M _ { \mathrm { * } } \gtrsim 2.5 M _ { \bigodot } ) , the position of the \mathrm { H _ { 2 } O } snowline is further from the central star compared with that around cooler , and less massive T Tauri stars .
Thus , the \mathrm { H _ { 2 } O } emission line fluxes from the region within the \mathrm { H _ { 2 } O } snowline are expected to be stronger .
In this paper , we calculate the chemical composition of a Herbig Ae disk using chemical kinetics .
Next , we calculate the \mathrm { H _ { 2 } O } emission line profiles , and investigate the properties of candidate water lines across a wide range of wavelengths ( from mid-infrared to sub-millimeter ) that can locate the position of the \mathrm { H _ { 2 } O } snowline .
Those line identified have small Einstein A coefficients ( \sim 10 ^ { -6 } -10 ^ { -3 } s ^ { -1 } ) and relatively high upper state energies ( \sim 1000K ) .
The total fluxes tend to increase with decreasing wavelengths .
We investigate the possibility of future observations ( e.g. , ALMA , SPICA/SMI-HRS ) to locate the position of the \mathrm { H _ { 2 } O } snowline .
Since the fluxes of those identified lines from Herbig Ae disks are stronger than those from T Tauri disks , the possibility of a successful detection is expected to increase for a Herbig Ae disk .