Precursors of the RNA World in Space: Detection of (Z)-1,2-ethenediol in the Interstellar Medium, a Key Intermediate in Sugar Formation

We present the first detection of (Z)-1,2-ethenediol, (CHOH)(2), the enol form of glycolaldehyde, in the interstellar medium toward the G+0.693-0.027 molecular cloud located in the Galactic Center. We have derived a column density of (1.8 +/- 0.1) x 10(13) cm(-2), which translates into a molecular abundance with respect to molecular hydrogen of 1.3 x 10(-10). The abundance ratio between glycolaldehyde and (Z)-1,2-ethenediol is similar to 5.2. We discuss several viable formation routes through chemical reactions from precursors such as HCO, H2CO, CHOH, or CH2CHOH. We also propose that this species might be an important precursor in the formation of glyceraldehyde (HOCH2CHOHCHO) in the interstellar medium through combination with the hydroxymethylene (CHOH) radical.

Automated summary

We report the first detection of (Z)-1,2-ethenediol, the enol form of glycolaldehyde, in a molecular cloud near the Galactic Center. The molecular abundance with respect to molecular hydrogen is determined, and the possible formation routes and its relation to glyceraldehyde are discussed.