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Article: Three-dimensional chemically homogeneous and bi-abundance photoionization models of the 'super-metal-rich' planetary nebula NGC 6153

TitleThree-dimensional chemically homogeneous and bi-abundance photoionization models of the 'super-metal-rich' planetary nebula NGC 6153
Authors
KeywordsIsm: abundances
Planetary nebulae: individual: ngc6153
Issue Date2011
PublisherBlackwell Publishing Ltd. The Journal's web site is located at http://www.blackwellpublishing.com/journals/MNR
Citation
Monthly Notices of the Royal Astronomical Society, 2011, v. 411 n. 2, p. 1035-1052 How to Cite?
AbstractDeep spectroscopy of the planetary nebula NGC6153 shows that its heavy element abundances derived from optical recombination lines (ORLs) are 10 times higher than those derived from collisionally excited lines (CELs), and points to the existence of H-deficient inclusions embedded in the diffuse nebula. In this study, we have constructed chemically homogeneous and bi-abundance three-dimensional photoionization models, using the Monte Carlo photoionization code mocassin. We attempt to reproduce the multiwaveband spectroscopic and imaging observations of NGC6153, and investigate the nature and origin of the postulated H-deficient inclusions, as well as their impacts on the empirical nebular analyses assuming a uniform chemical composition. Our results show that chemically homogeneous models yield small electron temperature fluctuations and fail to reproduce the strengths of ORLs from C, N, O and Ne ions. In contrast, bi-abundance models incorporating a small amount of metal-rich inclusions (∼1.3 per cent of the total nebular mass) are able to match all the observations within the measurement uncertainties. The metal-rich clumps, cooled down to a very low temperature (∼800K) by ionic infrared fine-structure lines, dominate the emission of heavy element ORLs, but contribute almost nil to the emission of most CELs. We find that the abundances of C, N, O and Ne derived empirically from CELs, assuming a uniform chemical composition, are about 30per cent lower than the corresponding average values of the whole nebula, including the contribution from the H-deficient inclusions. Ironically, in the presence of H-deficient inclusions, the traditional standard analysis of the optical helium recombination lines, assuming a chemically homogeneous nebula, overestimates the helium abundance by 40 per cent.
Persistent Identifierhttp://hdl.handle.net/10722/134734
ISSN
2015 Impact Factor: 4.952
2015 SCImago Journal Rankings: 2.806
ISI Accession Number ID
Funding AgencyGrant Number
STFC
HKU200909159007
NASA Science Mission DirectorateSMD-08-0633
SMD-09-1154
Funding Information:

We would like to thank the referee for the valuable comments, which helped improve the quality of the paper. The modelling was carried out on the SGI Altix330 System at the Department of Astronomy at Peking University, HP supercomputer operated by the Center for Computational Science and Engineering at Peking University and the Columbia supercomputer operated by the NASA Advanced Supercomputing (NAS) Division at Ames Research Center. We acknowledge our awards, SMD-08-0633 and SMD-09-1154, of High-End Computing (HEC) time on NAS and NCCS resources by the NASA Science Mission Directorate (SMD). We thank Johnny Chang for his able and generous support of our research using Columbia. This research has made use of NASA's Astrophysics Data System Bibliographic Services. BE is supported by an STFC Advanced Fellowship. YZ acknowledges financial support from the Seed Funding Programme for Basic Research in HKU (200909159007).

 

DC FieldValueLanguage
dc.contributor.authorYuan, H-B-
dc.contributor.authorLiu, XW-
dc.contributor.authorPequignot, D-
dc.contributor.authorRubin, R-
dc.contributor.authorErcolano, B-
dc.contributor.authorZhang, Y-
dc.date.accessioned2011-07-14T00:52:52Z-
dc.date.available2011-07-14T00:52:52Z-
dc.date.issued2011-
dc.identifier.citationMonthly Notices of the Royal Astronomical Society, 2011, v. 411 n. 2, p. 1035-1052-
dc.identifier.issn0035-8711-
dc.identifier.urihttp://hdl.handle.net/10722/134734-
dc.description.abstractDeep spectroscopy of the planetary nebula NGC6153 shows that its heavy element abundances derived from optical recombination lines (ORLs) are 10 times higher than those derived from collisionally excited lines (CELs), and points to the existence of H-deficient inclusions embedded in the diffuse nebula. In this study, we have constructed chemically homogeneous and bi-abundance three-dimensional photoionization models, using the Monte Carlo photoionization code mocassin. We attempt to reproduce the multiwaveband spectroscopic and imaging observations of NGC6153, and investigate the nature and origin of the postulated H-deficient inclusions, as well as their impacts on the empirical nebular analyses assuming a uniform chemical composition. Our results show that chemically homogeneous models yield small electron temperature fluctuations and fail to reproduce the strengths of ORLs from C, N, O and Ne ions. In contrast, bi-abundance models incorporating a small amount of metal-rich inclusions (∼1.3 per cent of the total nebular mass) are able to match all the observations within the measurement uncertainties. The metal-rich clumps, cooled down to a very low temperature (∼800K) by ionic infrared fine-structure lines, dominate the emission of heavy element ORLs, but contribute almost nil to the emission of most CELs. We find that the abundances of C, N, O and Ne derived empirically from CELs, assuming a uniform chemical composition, are about 30per cent lower than the corresponding average values of the whole nebula, including the contribution from the H-deficient inclusions. Ironically, in the presence of H-deficient inclusions, the traditional standard analysis of the optical helium recombination lines, assuming a chemically homogeneous nebula, overestimates the helium abundance by 40 per cent.-
dc.languageeng-
dc.publisherBlackwell Publishing Ltd. The Journal's web site is located at http://www.blackwellpublishing.com/journals/MNR-
dc.relation.ispartofMonthly Notices of the Royal Astronomical Society-
dc.rightsThe definitive version is available at www.blackwell-synergy.com-
dc.subjectIsm: abundances-
dc.subjectPlanetary nebulae: individual: ngc6153-
dc.titleThree-dimensional chemically homogeneous and bi-abundance photoionization models of the 'super-metal-rich' planetary nebula NGC 6153en_US
dc.typeArticleen_US
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0035-8711&volume=411&issue=2&spage=1035&epage=1052&date=2011&atitle=Three-dimensional+chemically+homogeneous+and+bi-abundance+photoionization+models+of+the+%27super-metal-rich%27+planetary+nebula+NGC+6153-
dc.identifier.emailZhang, Y: zhangy96@hku.hk-
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1111/j.1365-2966.2010.17732.x-
dc.identifier.scopuseid_2-s2.0-79551576250en_US
dc.identifier.hkuros186115-
dc.identifier.volume411-
dc.identifier.issue2-
dc.identifier.spage1035-
dc.identifier.epage1052-
dc.identifier.isiWOS:000286988800023-

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