The [S ii] Spectral Images of the Planetary Nebula NGC 7009. II. Major Axis
We derived position–velocity density distribution diagrams along the major (PA = 77°) axis of the elliptical planetary nebula NGC 7009 with the Keck HIRES [S ii ] 6716/6731 Å doublet spectral images. The average densities of the main shell and knots of NGC 7009 derived from the [S ii ] 6716/6731 Å f...
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal Supplement Series |
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| Online Access: | https://doi.org/10.3847/1538-4365/acad72 |
| _version_ | 1797701933959479296 |
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| author | Siek Hyung Seong-Jae Lee Masaaki Otsuka |
| author_facet | Siek Hyung Seong-Jae Lee Masaaki Otsuka |
| author_sort | Siek Hyung |
| collection | DOAJ |
| description | We derived position–velocity density distribution diagrams along the major (PA = 77°) axis of the elliptical planetary nebula NGC 7009 with the Keck HIRES [S ii ] 6716/6731 Å doublet spectral images. The average densities of the main shell and knots of NGC 7009 derived from the [S ii ] 6716/6731 Å fluxes integrated over the line of sight indicate a density range of N _e = 10 ^3.4 to 10 ^3.9 cm ^−3 , while the local densities from the volume fraction resolved in radial velocities along the line of sight show a considerably large range of about 10 ^2.8 –10 ^4.7 cm ^−3 . The derived projection angle of the major axis of the main shell is ψ ∼ 18.3° (±2°). Assuming that the main shell is an ellipsoidal shell with a ≃ 16″ and b ≃ 6″, we found the range of the expansion velocity, radius, and latitude of four knots and a hot bubble. The four knots at points in symmetrical positions are roughly aligned with the same axis of expansion of latitudes ϕ ∼ ±34.5° (±0.6°): one pair expands at about 35 km s ^−1 close to the main ellipsoidal shell, and the other expands rapidly at about 60 km s ^−1 at a distance of r ∼ 16″. In the latitude range ϕ = 65°–75°, the hot bubble of a relatively large structure expands rapidly with a velocity of 130–150 km s ^−1 . The four knots and hot bubble points, which expand faster than the main shell, appear to have been formed by two to three eruptions at a different epoch from the primary structure formation. |
| first_indexed | 2024-03-12T04:42:48Z |
| format | Article |
| id | doaj.art-4e749a015bdf4505906e51aa04c5ff2d |
| institution | Directory Open Access Journal |
| issn | 0067-0049 |
| language | English |
| last_indexed | 2024-03-12T04:42:48Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Supplement Series |
| spelling | doaj.art-4e749a015bdf4505906e51aa04c5ff2d2023-09-03T09:30:46ZengIOP PublishingThe Astrophysical Journal Supplement Series0067-00492023-01-012651210.3847/1538-4365/acad72The [S ii] Spectral Images of the Planetary Nebula NGC 7009. II. Major AxisSiek Hyung0https://orcid.org/0000-0003-0300-4624Seong-Jae Lee1https://orcid.org/0000-0002-2874-9529Masaaki Otsuka2Department of Earth Science (Astronomy), Chungbuk National University , Chungbuk 28644, Republic of Korea ; hyung@chungbuk.ac.krDepartment of Earth Science (Astronomy), Chungbuk National University , Chungbuk 28644, Republic of Korea ; hyung@chungbuk.ac.krOkayama Observatory, Kyoto University , Kamogata, Asakuchi, Okayama, 719-0232, JapanWe derived position–velocity density distribution diagrams along the major (PA = 77°) axis of the elliptical planetary nebula NGC 7009 with the Keck HIRES [S ii ] 6716/6731 Å doublet spectral images. The average densities of the main shell and knots of NGC 7009 derived from the [S ii ] 6716/6731 Å fluxes integrated over the line of sight indicate a density range of N _e = 10 ^3.4 to 10 ^3.9 cm ^−3 , while the local densities from the volume fraction resolved in radial velocities along the line of sight show a considerably large range of about 10 ^2.8 –10 ^4.7 cm ^−3 . The derived projection angle of the major axis of the main shell is ψ ∼ 18.3° (±2°). Assuming that the main shell is an ellipsoidal shell with a ≃ 16″ and b ≃ 6″, we found the range of the expansion velocity, radius, and latitude of four knots and a hot bubble. The four knots at points in symmetrical positions are roughly aligned with the same axis of expansion of latitudes ϕ ∼ ±34.5° (±0.6°): one pair expands at about 35 km s ^−1 close to the main ellipsoidal shell, and the other expands rapidly at about 60 km s ^−1 at a distance of r ∼ 16″. In the latitude range ϕ = 65°–75°, the hot bubble of a relatively large structure expands rapidly with a velocity of 130–150 km s ^−1 . The four knots and hot bubble points, which expand faster than the main shell, appear to have been formed by two to three eruptions at a different epoch from the primary structure formation.https://doi.org/10.3847/1538-4365/acad72Planetary nebulaeH II regionsInterstellar mediumPost-asymptotic giant branch |
| spellingShingle | Siek Hyung Seong-Jae Lee Masaaki Otsuka The [S ii] Spectral Images of the Planetary Nebula NGC 7009. II. Major Axis The Astrophysical Journal Supplement Series Planetary nebulae H II regions Interstellar medium Post-asymptotic giant branch |
| title | The [S ii] Spectral Images of the Planetary Nebula NGC 7009. II. Major Axis |
| title_full | The [S ii] Spectral Images of the Planetary Nebula NGC 7009. II. Major Axis |
| title_fullStr | The [S ii] Spectral Images of the Planetary Nebula NGC 7009. II. Major Axis |
| title_full_unstemmed | The [S ii] Spectral Images of the Planetary Nebula NGC 7009. II. Major Axis |
| title_short | The [S ii] Spectral Images of the Planetary Nebula NGC 7009. II. Major Axis |
| title_sort | s ii spectral images of the planetary nebula ngc 7009 ii major axis |
| topic | Planetary nebulae H II regions Interstellar medium Post-asymptotic giant branch |
| url | https://doi.org/10.3847/1538-4365/acad72 |
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