The following document lists the file abstract/IYAMAMUR_HVFLOW.abs
from catalogue VI/111.
A plain copy of the file
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We propose an observation of the high-velocity outflow of evolved objects with mid- and far-infrared atomic / ionic lines by SWS and LWS. The high-velocity outflows in the circumstellar envelope of evolved stars have been discovered mostly by radio molecular line observations. The velocity of the wind often exceeds 100km/s. Many of the objects are so called "proto-planetary nebulae" which lie between the AGB and planetary nebula phase. The mechanism of acceleration of the high-velocity wind has still not been understood. The purpose of the present observation is to clarify the physical conditions of the high-velocity flow and contiguous region in the envelope. The region is thought to be near the central star and the gas temperature is high. Atomic and ionic lines in mid- and far-infrared are good tracers of such warm gas. In addition, shocks between the high-velocity wind and the surrounding slowly expanding envelope play an important role to determine the physical conditions in the region, such as excitation or destruction of the molecules. These lines will provide us important information about this phenomenon. Our goal is to construct an unique model of the circumstellar envelope including the high-velocity outflow. Two spectrometers, SWS and LWS with Fabry-Perot are used in the observations. A total observation time of 23422sec is requested for the autumn launch and 24089sec for the spring launch.