Ref: ASTROimport-306

Herschel Planetary Nebula Survey (HerPlaNS). First detection of OH+ in planetary nebulae

Aleman, I. ; Ueta, T. ; Ladjal, D. ; Exter, K. M. ; Kastner, J. H. ; Montez, R. ; Tielens, A. G. G. M. ; Chu, Y.-H. ; Izumiura, H. ; McDonald, I. ; Sahai, R. ; Siódmiak, N. ; Szczerba, R. ; van Hoof, P. A. M. ; Villaver, E. ; Vlemmings, W. ; Wittkowski, M. ; Zijlstra, A. A.

published in Astronomy and Astrophysics, 566, pp. A79 (2014)

Abstract: Aims: We report the first detections of OH+ emission in planetary nebulae (PNe). Methods: As part of an imaging and spectroscopy survey of 11 PNe in the far-IR using the PACS and SPIRE instruments aboard the Herschel Space Observatory, we performed a line survey in these PNe over the entire spectral range between 51µm and 672µm to look for new detections. Results: The rotational emission lines of OH+ at 152.99, 290.20, 308.48, and 329.77µm were detected in the spectra of three planetary nebulae: NGC 6445, NGC 6720, and NGC 6781. Excitation temperatures and column densities derived from these lines are in the range of 27-47 K and 2 × 1010-4 × 1011 cm-2, respectively. Conclusions: In PNe, the OH+ rotational line emission appears to be produced in the photodissociation region (PDR) in these objects. The emission of OH+ is observed only in PNe with hot central stars (Teff> 100 000 K), suggesting that high-energy photons may play a role in OH+ formation and its line excitation in these objects, as seems to be the case for ultraluminous galaxies. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

DOI: 10.1051/0004-6361/201322940
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The record appears in these collections:
Royal Observatory of Belgium > Astronomy & Astrophysics
Science Articles > Peer Reviewed Articles

 Record created 2016-07-01, last modified 2016-07-06