Deep search for hydrogen peroxide toward pre- and protostellar objects

Astronomy and Astrophysics, vol. 636, pp. A114

Abstract

Context. In the laboratory, hydrogen peroxide (HOOH) was proven to be an intermediate product in the solid-state reaction scheme that leads to the formation of water on icy dust grains. When HOOH desorbs from the icy grains, it can be detected in the gas phase. In combination with water detections, it may provide additional information on the water reaction network. Hydrogen peroxide has previously been found toward ρ Oph A. However, further searches for this molecule in other sources failed. Hydrogen peroxide plays a fundamental role in the understanding of solid-state water formation and the overall water reservoir in young stellar objects (YSOs). Without further HOOH detections, it is difficult to assess and develop suitable chemical models that properly take into account the formation of water on icy surfaces. Aims. The objective of this work is to identify HOOH in YSOs and thereby constrain the grain surface water formation hypothesis. Methods. Using an astrochemical model based on previous work in combination with a physical model of YSOs, the sources R CrA-IRS 5A, NGC C1333-IRAS 2A, L1551-IRS 5, and L1544 were identified as suitable candidates for an HOOH detection. Long integration times on the APEX 12 m and IRAM 30 m telescopes were applied to search for HOOH signatures in these sources. Results. None of the four sources under investigation showed convincing spectral signatures of HOOH. The upper limit for HOOH abundance based on the noise level at the frequency positions of this molecule for the source R CrA-IRS 5A was close to the predicted value. For NGC 1333-IRAS 2A, L1544, and L1551-IRS 5, the model overestimated the hydrogen peroxide abundances. Conclusions. HOOH remains an elusive molecule. With only one secure cosmic HOOH source detected so far, namely ρ Oph A, the chemical model parameters for this molecule cannot be sufficiently well determined or confirmed in existing models. Possible reasons for the nondetections of HOOH are discussed.

Authors 9

1. Guido Fuchs

   University of Kassel

   Affiliation as printed

   Institute of Physics, University Kassel, Heinrich-Plett Str. 40, 34132 Kassel, Germany

2. Daniel Witsch

   University of Kassel

   Affiliation as printed

   Institute of Physics, University Kassel, Heinrich-Plett Str. 40, 34132 Kassel, Germany

3. Doris Herberth

   University of Kassel

   Affiliation as printed

   Institute of Physics, University Kassel, Heinrich-Plett Str. 40, 34132 Kassel, Germany

4. Marie Kempkes

   University of Kassel

   Affiliation as printed

   Institute of Physics, University Kassel, Heinrich-Plett Str. 40, 34132 Kassel, Germany

5. B. Stanclik

   University of Kassel

   Affiliation as printed

   Institute of Physics, University Kassel, Heinrich-Plett Str. 40, 34132 Kassel, Germany

6. J. Chantzos

   Max Planck Institute for Extraterrestrial Physics

   Affiliation as printed

   Max-Planck-Institute for Extraterrestrial Physics (MPE), Giessenbachstraße 1, 85748 Garching, Germany

7. H. Linnartz Aachen Laboratory for Astrophysics, Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands

8. Karl M. Menten

   Max Planck Institute for Radio Astronomy

   Affiliation as printed

   Max-Planck-Institut for Radio Astronomy (MPIfR), Auf dem Hügel 69, 53121 Bonn, Germany

9. Thomas F. Giesen

   University of Kassel

   Affiliation as printed

   Institute of Physics, University Kassel, Heinrich-Plett Str. 40, 34132 Kassel, Germany