1,3-Dihydroxyacetone in Sagittarius B2(N-LMH): The First Interstellar Ketose

We present here the results of an initial search for 1,3-dihydroxyacetone [or DHA, CO(CH₂OH)₂], the simplest ketose monosaccharide, toward the Sagittarius B2(N-LMH) hot core. Nine possible DHA emission lines have been observed with the Caltech Submillimeter Observatory, from which a rotational excitation temperature of 220+/-65 K and a beam-averaged column density of (4.9+/-2.2)×10¹⁵ cm^-2 are derived. If confirmed by additional observations, DHA would be among the most abundant complex molecules yet detected. DHA is not considered in any existing grain mantle or molecular cloud chemical model, highlighting the need for a more detailed investigation of the formation of prebiotic compounds in hot cores.