NGC 5189 explained

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.

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]

External links

• • • • • A Cosmic Holiday Ornament, Hubble-Style
• Southern African Large Telescope: Elusive Binary System

Notes and References

1. Web site: NGC 5189 (Mus) . dead . https://web.archive.org/web/20140114135738/https://www.southastrodel.com/NGC5189.htm . 2014-01-14 . 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 . 1983A&A...117...33P.
3. Danehkar . Ashkbiz . Karovska . Margarita . Maksym . W. Peter . Montez . Rodolfo . January 2018 . Mapping Excitation in the Inner Regions of the Planetary Nebula NGC 5189 Using HST WFC3 Imaging . The Astrophysical Journal . 852 . 2 . 87 . 1711.11111 . 2018ApJ...852...87D . 10.3847/1538-4357/aa9e8c . 0004-637X . 119365610 . free.
4. Manick . Rajeev . Miszalski . Brent . McBride . Vanessa . 2015-04-01 . 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 . en . 448 . 2 . 1789–1806 . 1501.03373 . 2015MNRAS.448.1789M . 10.1093/mnras/stv074 . 1365-2966 . 118600965 . free.
5. NGC 5189 . 2012-12-21.
6. Sabin . L. . Vázquez . R. . López . J. A. . García-Díaz . Ma. T. . Ramos-Larios . G. . 4 . 2012 . The filamentary Multi-Polar Planetary Nebula NGC 5189 . Revista Mexicana de Astronomía y Astrofísica . 48 . 165–76 . 1203.1297 . 2012RMxAA..48..165S.