Water in K and M giant stars unveiled by ISO

摘要: Based on the spectra obtained with Infrared Space Observatory, ISO, we detected 6.3m bands of water in late K giant Aldebaran ( Tau) and several early M stars (between M0 M3.5), which have been deemed to be too warm for tri-atomic H2O molecule reside their photospheres. The column densities range (0:2 2)10 18 molecules cm 2 our sample excitation temperatures are 1500 or higher. Thus, not originating cool stellar winds either. presence was quite unexpected from traditional picture atmosphere red star consisting photosphere, hot chromosphere, wind. We conrm that a rather forming region should exist as new component this general phenomenon late-type stars.