An investigation of the 3-mu m emission bands in planetary nebulae
Spectra are presented of 21 planetary nebulae spanning the well-known, but still unidentified, narrow emission features at 3.2-3.6 μm. The equivalent width of the 3.29-μm emission band is strongly correlated with the gas-phase carbon-to-oxygen ratio, as expected for a band origin in carbon-rich grai...
| Main Authors: | , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
1996
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| _version_ | 1826302024704065536 |
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| author | Roche, P Lucas, P Hoare, MG Aitken, D Smith, C |
| author_facet | Roche, P Lucas, P Hoare, MG Aitken, D Smith, C |
| author_sort | Roche, P |
| collection | OXFORD |
| description | Spectra are presented of 21 planetary nebulae spanning the well-known, but still unidentified, narrow emission features at 3.2-3.6 μm. The equivalent width of the 3.29-μm emission band is strongly correlated with the gas-phase carbon-to-oxygen ratio, as expected for a band origin in carbon-rich grains or molecules. It displays an approximately linear dependence upon the C/O ratio, with a threshold near C/O ∼0.6. The emission band is present in 18 of the 21 nebulae, being absent in three of the six oxygen-rich objects and only weakly present in a fourth. The profile of the , 3.29-μm band is closely similar in all of the nebulae and distinct from the band profile seen in some stellar envelopes. Weaker emission features in the 3.4-3.5 μm region are detected in nine objects, and are prominent only in nitrogen-rich type I nebulae. The intensity of the 3.4-μm feature in these objects is correlated with that of the 3.29-μm band, while the ratio of the two bands is strongly correlated with the nitrogen abundance. Possible explanations for this behaviour are discussed. |
| first_indexed | 2024-03-07T05:41:15Z |
| format | Journal article |
| id | oxford-uuid:e5a4c40e-2e96-45a0-b49b-47ad3f74aaef |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T05:41:15Z |
| publishDate | 1996 |
| record_format | dspace |
| spelling | oxford-uuid:e5a4c40e-2e96-45a0-b49b-47ad3f74aaef2022-03-27T10:25:27ZAn investigation of the 3-mu m emission bands in planetary nebulaeJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:e5a4c40e-2e96-45a0-b49b-47ad3f74aaefEnglishSymplectic Elements at Oxford1996Roche, PLucas, PHoare, MGAitken, DSmith, CSpectra are presented of 21 planetary nebulae spanning the well-known, but still unidentified, narrow emission features at 3.2-3.6 μm. The equivalent width of the 3.29-μm emission band is strongly correlated with the gas-phase carbon-to-oxygen ratio, as expected for a band origin in carbon-rich grains or molecules. It displays an approximately linear dependence upon the C/O ratio, with a threshold near C/O ∼0.6. The emission band is present in 18 of the 21 nebulae, being absent in three of the six oxygen-rich objects and only weakly present in a fourth. The profile of the , 3.29-μm band is closely similar in all of the nebulae and distinct from the band profile seen in some stellar envelopes. Weaker emission features in the 3.4-3.5 μm region are detected in nine objects, and are prominent only in nitrogen-rich type I nebulae. The intensity of the 3.4-μm feature in these objects is correlated with that of the 3.29-μm band, while the ratio of the two bands is strongly correlated with the nitrogen abundance. Possible explanations for this behaviour are discussed. |
| spellingShingle | Roche, P Lucas, P Hoare, MG Aitken, D Smith, C An investigation of the 3-mu m emission bands in planetary nebulae |
| title | An investigation of the 3-mu m emission bands in planetary nebulae |
| title_full | An investigation of the 3-mu m emission bands in planetary nebulae |
| title_fullStr | An investigation of the 3-mu m emission bands in planetary nebulae |
| title_full_unstemmed | An investigation of the 3-mu m emission bands in planetary nebulae |
| title_short | An investigation of the 3-mu m emission bands in planetary nebulae |
| title_sort | investigation of the 3 mu m emission bands in planetary nebulae |
| work_keys_str_mv | AT rochep aninvestigationofthe3mumemissionbandsinplanetarynebulae AT lucasp aninvestigationofthe3mumemissionbandsinplanetarynebulae AT hoaremg aninvestigationofthe3mumemissionbandsinplanetarynebulae AT aitkend aninvestigationofthe3mumemissionbandsinplanetarynebulae AT smithc aninvestigationofthe3mumemissionbandsinplanetarynebulae AT rochep investigationofthe3mumemissionbandsinplanetarynebulae AT lucasp investigationofthe3mumemissionbandsinplanetarynebulae AT hoaremg investigationofthe3mumemissionbandsinplanetarynebulae AT aitkend investigationofthe3mumemissionbandsinplanetarynebulae AT smithc investigationofthe3mumemissionbandsinplanetarynebulae |