Search for HOOH in Orion

Abstract

Context: The abundance of key molecules determines the level of cooling that is necessary for the formation of stars and planetary systems. In this context, one needs to understand the details of the time dependent oxygen chemistry, leading to the formation of molecular oxygen and water. Aims: We aim to determine the degree of correlation between the occurrence of O2 and HOOH (hydrogen peroxide) in star-forming molecular clouds. We first detected O2 and HOOH in the rho Ophiuchi cloud (core A), we now search for HOOH in Orion Molecular Cloud OMC A, where O2 has also been detected. Methods: We mapped a 3 arcmin times 3 arcmin region around Orion H2-Peak 1 with the Atacama Pathfinder Experiment (APEX). In addition to several maps in two transitions of HOOH, viz. 219.17 GHz and 251.91 GHz, we obtained single-point spectra for another three transitions towards the position of maximum emission. Results: Line emission at the appropriate LSR-velocity (Local Standard of Rest) and at the level of greater or equal to 4 sigma was found for two transitions, with lower S/N (2.8 - 3.5 sigma) for another two transitions, whereas for the remaining transition, only an upper limit was obtained. The emitting region, offset 18 arcsec south of H2-Peak 1, appeared point-like in our observations with APEX. Conclusions: The extremely high spectral line density in Orion makes the identification of HOOH much more difficult than in rho Oph A. As a result of having to consider the possible contamination by other molecules, we left the current detection status undecided.

4 pages, 2 figures, accepted for publication in Astronomy and Astrophysics

References in corpus (7)

• Molecular oxygen in the rho Ophiuchi cloud
• Detection of interstellar hydrogen peroxide
• Deep observations of O2 toward a low-mass protostar with Herschel-HIFI
• Detection of the hydroperoxyl radical HO2 toward ρOph A: Additional constraints on the water chemical network
• Herschel HIFI observations of O${}_2$ toward Orion: special conditions for shock enhanced emission
• Herschel Search for O2 Toward the Orion Bar
• Characterizing the chemical pathways for water formation -- A deep search for hydrogen peroxide

Cited by in corpus (4)

• Quantum tunneling during interstellar surface-catalyzed formation of water: the reaction H + H${}_2$O${}_2$ $\to$ H${}_2$O + OH
• Influence of surface and bulk water ice on the reactivity of a water-forming reaction
• A Search for O_2 in CO-depleted Molecular Cloud Cores with Herschel
• Deep search for hydrogen peroxide toward pre- and protostellar objects -- Testing the pathway of grain surface water formation