Detection of interstellar hydrogen peroxide

TL;DR

This study reports the first detection of interstellar hydrogen peroxide (HOOH) in the { ho} Oph A cloud core, revealing its abundance and spatial distribution, and providing insights into oxygen and water chemistry in space.

Contribution

It is the first detection of HOOH in the interstellar medium, with detailed analysis of its abundance and excitation conditions in a specific cloud core.

Findings

Detected three spectral lines of HOOH in { ho} Oph A

HOOH emission extends over 0.05 pc in the cloud core

HOOH abundance relative to H_2 is about 1×10^(-10)

Abstract

The molecular species hydrogen peroxide, HOOH, is likely to be a key ingredient in the oxygen and water chemistry in the interstellar medium. Our aim with this investigation is to determine how abundant HOOH is in the cloud core {\rho} Oph A. By observing several transitions of HOOH in the (sub)millimeter regime we seek to identify the molecule and also to determine the excitation conditions through a multilevel excitation analysis. We have detected three spectral lines toward the SM1 position of {\rho} Oph A at velocity-corrected frequencies that coincide very closely with those measured from laboratory spectroscopy of HOOH. A fourth line was detected at the 4{\sigma} level. We also found through mapping observations that the HOOH emission extends (about 0.05 pc) over the densest part of the {\rho} Oph A cloud core. We derive an abundance of HOOH relative to that of H_2 in the SM1 core of about 1\times10^(-10). To our knowledge, this is the first reported detection of HOOH in the interstellar medium.