the unidentified 21 micron emission feature was first discovered using the iras low resolution spectra (kwok, volk, and hrivnak 1989). the sources that show this emission feature have been limited to a small number of carbon-rich stars which are in the post-asymptotic giant branch phase of evolution. while many suggestions have been made as to the origin of this feature, there is no consensus on this question. however, there are indications that the 21 micron feature may be related to the uie features which are usually attributed to pah molecules. of the 4 sources where the feature was originally identified, iras 07134+1005 = sao 96709 is the prototype because it has the strongest 21 micron feature and is quite bright in the far-infrared. this star is near the iso sky hole and therefore is not currently scheduled for any iso observations. it is important to obtain iso sws01 and lws01 observations of this source to allow the identification of any features that accompany the 21 micron feature and to allow detailed study of the continuum properties of whatever type of dust carries the 21 micron feature.
Instrument
LWS01 , SWS01
Temporal Coverage
1997-11-07T06:25:58Z/1997-11-07T08:09:30Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the world's first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
