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. (2014). Herschel Planetary Nebula Survey (HerPlaNS): first detection of OH+ in planetary nebulae. Astron. Astrophys. 566: A79. https://dx.doi.org/10.1051/0004-6361/201322940
In: Astronomy & Astrophysics (Les Ulis). EDP Sciences: Les Ulis. ISSN 0004-6361; e-ISSN 1432-0746, meer
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| Author keywords |
astrochemistry / circumstellar matter / planetary nebulae: general / planetary nebulae: individual: NGC 6445 / planetary nebulae: individual: NGC 6720 / planetary nebulae: individual: NGC 6781 |
| Auteurs | | Top |
- Aleman, I.
- Ueta, T.
- Ladjal, D.
- Exter, K.M., meer
- Kastner, J.H.
- Montez, R.
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- Tielens, A.G.G.M.
- Chu, Y.-H.
- Izumiura, H.
- McDonald, I.
- Sahai, R.
- Siódmiak, N.
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- Szczerba, R.
- van Hoof, P.A.M.
- Villaver, E.
- Vlemmings, W.
- Wittkowski, M.
- Zijlstra, A.A.
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| 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. |
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