Named in memory of Marc Aaronson (1950–1987), associate professor of astronomy at the University of Arizona, killed in a tragic accident at the 4-m telescope at Kitt Peak. After completing his dissertation on the infrared properties of spiral galaxies, Aaronson demonstrated the determination of relative distances of galaxies independently of redshifts and detected the decelerative effect of the Virgo cluster on the Hubble flow. Observations of globular clusters in the Magellanic clouds showed carbon stars to be a characteristic of stellar populations of intermediate age, and his measurement of the large velocity dispersion of carbon stars in dwarf spheroidal galaxies suggested that even the smallest galaxies possess halos of cold dark matter. (M 12016) _ _.