NGC 5189

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.

NGC 5189
Emission nebula
Planetary nebula
NGC 5189 image taken with the Hubble Space Telescope on July 6, 2012
Observation data: J2000.0 epoch
Right ascension13h 33m 32.97s
Declination−65° 58′ 26.7″
Distance3000 ly ly
Apparent magnitude (V)8.2, 8.5p
Apparent dimensions (V)90 × 62 arcsec
ConstellationMusca
Physical characteristics
Radius~1 ly ly
Absolute magnitude (V)-
Notable featuresA peculiar PN with a binary in the center
DesignationsSpiral 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]

References
  1. Classic Deep-Sky and Double Stars : NGC 5189 (Mus) Southern Astronomical Delights
  2. Phillips J. P.; Reay N. K. (1983). "Ansae and the precession of central stars in planetary nebulae - The cases of NGC 5189 and NGC 6826". Astronomy and Astrophysics. 117: 33–37. Bibcode:1983A&A...117...33P.
  3. Danehkar, A.; Karovska, M.; Maksym, W.P.; Montez Jr., R. (2018). "Mapping Excitation in the Inner Regions of the Planetary Nebula NGC 5189 using HST WFC3 Imaging". Astrophys. J. 852 (2): 87. arXiv:1711.11111. Bibcode:2018ApJ...852...87D. doi:10.3847/1538-4357/aa9e8c. S2CID 119365610.
  4. Manick R.; Miszalski B.; McBride V. (2015). "A radial velocity survey for post-common-envelope Wolf-Rayet central stars of planetary nebulae: first results and discovery of the close binary nucleus of NGC 5189". Monthly Notices of the Royal Astronomical Society. 448 (2): 1789–1806. arXiv:1501.03373. Bibcode:2015MNRAS.448.1789M. doi:10.1093/mnras/stv074. S2CID 118600965.
  5. "NGC 5189". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 21 December 2012.
  6. SABIN L.; VAZQUEZ R.; LOPEZ J.A.; GARCIA-DIAZ M.T.; et al. (2012). "The filamentary multi-polar planetary nebula NGC 5189" (PDF). Rev. Mex. Astron. Astrofís. 48: 165–76. arXiv:1203.1297. Bibcode:2012RMxAA..48..165S.

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