Characterization of (CH2OH)2 in High Mass Young Stellar Object NGC 7538 IRS 1

The utility of complex organic molecules as probes of star formation and astrophysical environments depends on understanding of complex chemistry in protostellar environments. Existing protostellar models of hot core chemistry predict very low abundances of ethylene glycol, (CH2OH)2, a very large and hydrogen rich complex molecule, in star-forming regions. However, recent observations of Comet Hale-Bopp and Central Molecular Zone (CMZ) clouds have suggested that (CH2OH)2 can be produced in higher quantities than previously assumed. However, since these sources have extreme environmental conditions that complicate analysis of the chemistry, we cannot directly compare these results to current model predictions. As such, we examine 16 GHz of spectra from high mass young stellar object (YSO) NGC 7531 IRS 1 from the IRAM 30m telescope to determine the molecular abundance and excitation temperature of (CH2OH)2. Since NGC 7538 IRS 1 is an archetypal hot core, we can directly test current model predictions and benchmark the relative importance of different stages of star formation region complex chemistry. The column density and excitation temperature is calculated in two ways: by qualitative fitting of the most promising line candidates and via the rotation diagram method. We find that current models strongly underestimate (CH2OH)2, providing the first indication that (CH2OH)2 is much more common in star-forming regions. Since laboratory experiments have linked (CH2OH)2 to warm ice photochemistry, the results imply that this stage in star formation and the formation pathways of very complex molecules such as (CH2OH)2 are of greater relative chemical importance than previously assumed