Key points are not available for this paper at this time.
Small aperture 10. 2 micron measurements of normal elliptical galaxies show that for almost all of these galaxies the 12 micron emission seen by IRAS is extended on the scale of the galaxy. NGC 1052 and NGC 3998 are exceptions to this; much of their 10-12 micron emission comes from the inner regions of the galaxies and may be associated with their active nuclei, as is the case for many radio galaxies. The distribution of the infrared light and the infrared colors of elliptical galaxies suggest that the most plausible source of the 12 micron emission is photospheric and circumstellar emission from cool evolved red giant stars. The 12 micron emission is well in excess of that expected from photospheric emission alone; about 40% of it probably comes from circumstellar dust. The 12 and 2. 2 micron measurements are used to derive a total mass-loss rate of 0. 0021 L₂. 2_/Lₛun_ Mₛun_ Gyr^-1^ for the evolved giant stars in elliptical galaxies in excellent agreement with earlier and completely independent estimates based on optical luminosities and stellar evolutionary considerations.
Knapp et al. (Sun,) studied this question.