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Article: Molecular line emissions from the photodissociation region of NGC 7027
Title | Molecular line emissions from the photodissociation region of NGC 7027 |
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Authors | |
Keywords | Ism: Molecules Planetary Nebulae: Individual (Ngc 7027) Radio Lines: Ism |
Issue Date | 2001 |
Publisher | Institute of Physics Publishing Ltd. The Journal's web site is located at http://iopscience.iop.org/0004-637X |
Citation | The Astrophysical Journal, 2001, v. 562 n. 2 pt. 1, p. 824-841 How to Cite? |
Abstract | We have observed or searched for 11 molecular species in 17 transitions in the 200 and 300 GHz bands in the young planetary nebula NGC 7027. The results include a first detection of C 2H in this source. The observed spectra of HCO +, H 13CO +, HCN, CN, C 2H, and CO + show line widths wider than that of bulk CO emission but coincident with the full width at detection limit of weak wings in CO spectra. The HCO +, HCN, and CN emitting regions have a size of about 13″, significantly smaller than that of the CO emitting region. Thus, the emission of all the observed molecules other than CO and 13CO must originate from a very small volume compared with the entire CO envelope. Excitation analyses of six molecules with electron and neutral collisions at a gas temperature of 800 K yield similar density estimates ranging from 1.3 to 5 × 10 5 cm -3. Estimated column densities for HCO +, HCN, CN, CO +, and C 2H are in good agreement with predictions by a chemical model for the photodissociation region of NGC 7027. These analyses suggest that photochemistry is active in NGC 7027 and the observed molecular emissions (except CO) originate from the H 2 photodissociation zone of the object. © 2001. The American Astronomical Society. All rights reserved. |
Persistent Identifier | http://hdl.handle.net/10722/179646 |
ISSN | 2023 Impact Factor: 4.8 2023 SCImago Journal Rankings: 1.905 |
ISI Accession Number ID | |
References |
DC Field | Value | Language |
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dc.contributor.author | Hasegawa, TI | en_US |
dc.contributor.author | Kwok, S | en_US |
dc.date.accessioned | 2012-12-19T10:02:14Z | - |
dc.date.available | 2012-12-19T10:02:14Z | - |
dc.date.issued | 2001 | en_US |
dc.identifier.citation | The Astrophysical Journal, 2001, v. 562 n. 2 pt. 1, p. 824-841 | en_US |
dc.identifier.issn | 0004-637X | en_US |
dc.identifier.uri | http://hdl.handle.net/10722/179646 | - |
dc.description.abstract | We have observed or searched for 11 molecular species in 17 transitions in the 200 and 300 GHz bands in the young planetary nebula NGC 7027. The results include a first detection of C 2H in this source. The observed spectra of HCO +, H 13CO +, HCN, CN, C 2H, and CO + show line widths wider than that of bulk CO emission but coincident with the full width at detection limit of weak wings in CO spectra. The HCO +, HCN, and CN emitting regions have a size of about 13″, significantly smaller than that of the CO emitting region. Thus, the emission of all the observed molecules other than CO and 13CO must originate from a very small volume compared with the entire CO envelope. Excitation analyses of six molecules with electron and neutral collisions at a gas temperature of 800 K yield similar density estimates ranging from 1.3 to 5 × 10 5 cm -3. Estimated column densities for HCO +, HCN, CN, CO +, and C 2H are in good agreement with predictions by a chemical model for the photodissociation region of NGC 7027. These analyses suggest that photochemistry is active in NGC 7027 and the observed molecular emissions (except CO) originate from the H 2 photodissociation zone of the object. © 2001. The American Astronomical Society. All rights reserved. | en_US |
dc.language | eng | en_US |
dc.publisher | Institute of Physics Publishing Ltd. The Journal's web site is located at http://iopscience.iop.org/0004-637X | en_US |
dc.relation.ispartof | The Astrophysical Journal | en_US |
dc.subject | Ism: Molecules | en_US |
dc.subject | Planetary Nebulae: Individual (Ngc 7027) | en_US |
dc.subject | Radio Lines: Ism | en_US |
dc.title | Molecular line emissions from the photodissociation region of NGC 7027 | en_US |
dc.type | Article | en_US |
dc.identifier.email | Kwok, S: deannote@hku.hk | en_US |
dc.identifier.authority | Kwok, S=rp00716 | en_US |
dc.description.nature | published_or_final_version | en_US |
dc.identifier.doi | 10.1086/323856 | en_US |
dc.identifier.scopus | eid_2-s2.0-0012694784 | en_US |
dc.relation.references | http://www.scopus.com/mlt/select.url?eid=2-s2.0-0012694784&selection=ref&src=s&origin=recordpage | en_US |
dc.identifier.volume | 562 | en_US |
dc.identifier.issue | 2 pt. 1 | en_US |
dc.identifier.spage | 824 | en_US |
dc.identifier.epage | 841 | en_US |
dc.identifier.isi | WOS:000172572600022 | - |
dc.publisher.place | United Kingdom | en_US |
dc.identifier.scopusauthorid | Hasegawa, TI=7404173711 | en_US |
dc.identifier.scopusauthorid | Kwok, S=22980498300 | en_US |
dc.identifier.issnl | 0004-637X | - |