Introduction

Abstract

This chapter is the introduction section of our thesis, “Water snowline in protoplanetary disks”. Observationally locating the position of the H$_{2}$O snowline in protoplanetary disks is important to understand the planetesimal and planet formation processes, and the water trail to rocky planets. The line profiles from disks are usually affected by doppler shift due to Keplerian rotation. Thus, the line profiles are sensitive to the radial distribution of the emitting regions of lines. However, water lines which have been obtained by previous infrared spectroscopic observations mainly traced the disk surface and the cold water reservoir outside the H$_{2}$O snowline. Thus, they are not good direct tracer of the H$_{2}$O snowline. In this thesis, we proposed a method to locate the H$_{2}$O snowline position more directly by analyzing the H$_{2}$O line profiles which can be obtained by high dispersion spectroscopic observations across a wide wavelength rage (from mid-infrared to sub-millimeter, e.g., SPICA, ALMA) and selected based on specific criteria.