Magellanic Cloud Planetary Nebulae

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Notes on SMC planetary nebulae

See the corresponding table of basic measurements, including coordinates, dimensions, and morphological classifications.

SMC-J-3

This round PN has a bright hemisphere of emission to the NE, making the whole quite asymmetric in appearance. H-alpha and [O III] are very strong, but [N II] is fairly weak; these lines all show the same morphological structures. [S II] and He I, are also present but very weak, and [O I] 6300 may be marginally detected. The CS may be detected in the continuum image.

SMC-J-4

This object is not very well resolved. The field is crowded, making the ID on the clear image a little uncertain. I think it is at X=542, Y=511. The spectrum is reasonably well exposed, and shows pretty much all the lines: H-beta, [O III] 4959+5007, [O I] 6300+63, [S III] 6312, [N II] 6548+83, H-alpha, He I 6678, and [S II].

SMC-J-8

This bipolar PN has a distinct dark band that divides the bright core into two, unequal lobes. This looks very much like a case of a strong bipolar ring, viewed some distance from the plane. A faint bipolar structure is even evident up to 2 arcsec from the center (particularly to the south), but the ribbed, fan-like structure is projected off-center on the sky. H-alpha and [O III] are very strong, but [N II] is fairly weak; these lines all show the same morphological structures. [S II] and He I, are also present but very weak, and [O I] 6300 may be marginally detected. The CS may be detected in the continuum image, and possibly also in the G750M spectrum.

SMC-J-11

This round PN is barely resolved. Its appearance is nearly stellar in the continuum, but appears shell- or ring-like in the lower ionization lines. H-alpha and [O III] are very strong, but [N II], He I, and [S II] are very weak but detected. Also weak are [O I] 6300, 6363, and [S III] 6312. The CS may be detected in the continuum image.

SMC-J-23

This object is apparently spatially unresolved, and the ID on the clear image is difficult. (Recall that we did not take wavecals or an image through the slit to save on overhead.) Based on the MSM repeatability & the positions of the continuous spectra, I suspect the PN is at X=505, Y=522 in the image. Will have to verify that. The spectrum shows strong and broad H-alpha, somewhat weaker & broad [N II], and detectible He I 6678. No [S II], and no [O I]. We don't have a G430M spectrum. I haven't had a chance to measure the H-alpha velocity width yet, but it appears to be ~200-300 km/s. Pretty broad for a PN. Boroson & Liebert (1989) also noted a peculiar spectrum (v. strong He II and weak [O III], as I recall), but doubted it could be a symbiotic with a Giant companion as the red stellar continuum would have been apparent. Perhaps a symbiotic with a M.S. companion? If it is a PN, maybe the H-alpha flux has changed since B&L published their spectra?

SMC-J-27

This object is roughly box-shaped, and may be the remnant of a bipolar. The nebula is barely detected in the broad-band exposure, at roughly 20 counts/pixel above the background. The spectrum shows faint [N II] emission, with some hint of H-alpha emission. The G750M exposure was only about one-quarter of the desired duration, but was nonetheless about as long as could be accomodated in a SNAPSHOT. No central star is detected.

SMC-MA-1682

This is an extreme bipolar PN, with a prominent central ring. The H-alpha and [N II] lines are very strong in the spectrum, and [S II] is barely detected; no other lines are detected. We don't have a blue spectrum for this one, so no measurement of [O III]. The CS is easily detected in the continuum image.

SMC-MA-1762

This is an elliptical PN, with a mildly bi-nebulous inner core. No lines other than H-alpha are detected in the spectrum: no [N II], no He I, etc. We don't have a blue spectrum for this one, so no measurement of [O III]. The CS is easily detected in the continuum image.

SMC-MG-08

This elliptical PN has a very distinct ring structure, with a hint of ansae that extend ~0.1 arcsec along the major axis from the 10% contour. H-alpha is very strong, and [N II] is apparent but weaker, and [S II] is very weak. No other lines are detected in the G750M spectrum. H-beta is well exposed, and [O III] is only a bit stronger. The morphology in [O III] different in detail, in that the emission comes primarily from a ring that is inside the emission from most other lines. An ionization map would be interesting. The CS is exceptionally bright in the continuum image; could it be a MS binary companion to the true CS?

SMC-MG-13

This elliptical PN has a very knotty ring structure, with ansae that extend ~0.3 arcsec from the 10% contour. H-alpha is very strong, but neither [N II] nor any other line is detected in the G750M spectrum. The CS is easily detected in the continuum image.

SMC-SMP-08

This is a round PN, with somewhat elliptical inner contours. H-alpha and [O III] are very strong, with [N II] and He I at the ~1% level, and [S II] weaker still. [O I] is absent. The CS is detected in the continuum image, but there is a significant contribution from the nebular emission.

SMC-SMP-14

This round PN has a distinctly bi-nebulous inner core, and faint ansae that extend ~0.3 arcsec from the 10% contour, along a line roughly 45° from the axis of symmetry defined by the lobes. H-alpha is very strong, and [N II] is detected in the spectrum, but is very weak. [S II] and He I, are also present but weak. [O III] is quite strong. The CS is easily detected in the continuum image.

SMC-SMP-17

This is a round PN, with a very faint outer halo that is detected in the continuum image, in H-alpha, and in [O III] at the ~0.4% contour level. The inner portion is somewhat elliptical in all the observed lines except [N II], where it is ring-like. H-alpha is very strong, and [N II] is present but very weak. The CS is detected in the continuum image, but there is a significant contribution from the nebular emission.

SMC-SMP-20

This PN is bright but unresolved. H-alpha and [O III] are very strong, with [N II] at the ~1% level, and He I, [S II], and [O I] weaker still. The CS is detected in the continuum image, but there is a significant contribution from the nebular emission.

SMC-SMP-26

This is a very small point-symmetric PN two arms that extend from the NE and SW of the center. H-alpha is fairly strong, but [N II] is nearly as bright, and shows the arms much more clearly. No CS is detected in the continuum image.

SMC-SMP-27

This is a round PN, with somewhat elliptical inner contours. H-alpha and [O III] are very strong, with [N II] at the ~1% level, and He I, [S II], and [O I] weaker still. The CS is detected in the continuum image, but there is a significant contribution from the nebular emission.

SMC-SP-34

This is a round PN, with a faint outer halo that is detected in the continuum image and in H-alpha, at the 5% contour level. The inner portion shows significant asymmetry in all the observed lines, in that the western edge is much brighter. H-alpha is fairly strong, and [N II] is present but much weaker. No CS is detected in the continuum image.


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