NGC 5189
Planetary nebula in the constellation Musca
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NGC 5189 (Gum 47, IC 4274, nicknamed Spiral Planetary Nebula) is a planetary nebula in the constellation Musca. It was discovered by James Dunlop on 1 July 1826, who catalogued it as Δ252.[1] For many years, well into the 1960s, it was thought to be a bright emission nebula. It was Karl Gordon Henize in 1967 who first described NGC 5189 as quasi-planetary based on its spectral emissions.
| Emission nebula | |
|---|---|
| Planetary nebula | |
NGC 5189 image taken with the Hubble Space Telescope on July 6, 2012 | |
| Observation data: J2000.0 epoch | |
| Right ascension | 13h 33m 32.97s |
| Declination | −65° 58′ 26.7″ |
| Distance | 3000 ly |
| Apparent magnitude (V) | 8.2, 8.5p |
| Apparent dimensions (V) | 90 × 62 arcsec |
| Constellation | Musca |
| Physical characteristics | |
| Radius | ~1 ly |
| Absolute magnitude (V) | - |
| Notable features | A peculiar PN with a binary in the center |
| Designations | Spiral Planetary Nebula, Gum 47, IC 4274, He2-94, Sa2-95, PK 307-3.1 |
Seen through the telescope it seems to have an S shape, reminiscent of a barred spiral galaxy. The S shape, together with point-symmetric knots in the nebula, have for a long time hinted to astronomers that a binary central star is present.[2] The Hubble Space Telescope imaging analysis showed that this S shape structure is indeed two dense low-ionization regions: one moving toward the north-east and another one moving toward the south-west of the nebula,[3] which could be a result of a recent outburst from the central star. Observations with the Southern African Large Telescope have finally found a white dwarf companion in a 4.04 day orbit around the rare low-mass Wolf-Rayet type central star of NGC 5189.[4] NGC 5189 is estimated to be 546 parsecs[5] or 1,780 light years away from Earth. Other measurements have yielded results up to 900 parsecs (~3000 light-years).[6]
There is a very similar planetary nebula in the Large Magellanic Cloud, N66, which also contains a Wolf-Rayet nucleus.
