Precursors of the RNA-world in space: Detection of ($Z$)-1,2-ethenediol in the interstellar medium, a key intermediate in sugar formation

Abstract

We present the first detection of (Z)-1,2-ethenediol, (CHOH) 2 , the enol form of glycolaldehyde, in the interstellar medium towards the G+0.693-0.027 molecular cloud located in the Galactic Center. We have derived a column density of (1.8±0.1)×10 13 cm −2 , which translates into a molecular abundance with respect to molecular hydrogen of 1.3×10 −10 . The abundance ratio between glycolaldehyde and (Z)-1,2-ethenediol is ∼5.2. We discuss several viable formation routes through chemical reactions from precursors such as HCO, H 2 CO, HCOH or CH 2 CHOH. We also propose that this species might be an important precursor in the formation of glyceraldehyde (HOCH 2 CHOHCHO) in the interstellar medium through combination with the hydroxymethylene (CHOH) radical.