Detection of the hydroperoxyl radical HO2 toward rho Ophiuchi A
Artikel i vetenskaplig tidskrift, 2012

Context. Hydrogen peroxide (HOOH) was recently detected toward ρ Oph A. Subsequent astrochemical modeling that included reactions in the gas phase and on the surface of dust grains was able to explain the observed abundance, and highlighted the importance of grain chemistry in the formation of HOOH as an intermediate product in water formation. This study also predicted that the hydroperoxyl radical HO2, the precursor of HOOH, should be detectable. Aims. We aim at detecting the hydroperoxyl radical HO2 in ρ Oph A. Methods. We used the IRAM 30 m and the APEX telescopes to target the brightest HO2 lines at about 130 and 260 GHz. Results. We detect five lines of HO2 (comprising seven individual molecular transitions). The fractional abundance of HO2 is found to be about 10-10, a value similar to the abundance of HOOH. This observational result is consistent with the prediction of the above mentioned astrochemical model, and thereby validates our current understanding of the water formation on dust grains. Conclusions. This detection, anticipated by a sophisticated gas-grain chemical model, demonstrates that models of grain chemistry have improved tremendously and that grain surface reactions now form a crucial part of the overall astrochemical network.

ISM: molecules

astrochemistry

ISM: individual objects: ρ Ophiuchi A

ISM: abundances

line: identification

Författare

B. Parise

Max Planck-institutet

Per Bergman

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

F. Du

Max Planck-institutet

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 541 L11- L11

Ämneskategorier

Astronomi, astrofysik och kosmologi

Atom- och molekylfysik och optik

Fundament

Grundläggande vetenskaper

Infrastruktur

Onsala rymdobservatorium

DOI

10.1051/0004-6361/201219379

Mer information

Senast uppdaterat

2018-02-21