NGC 5189

{{short description|Planetary nebula in the constellation Musca}}

{{Use dmy dates|date=April 2014}}

{{Planetary nebula |

| name = NGC 5189

| image = 300px

| caption = NGC 5189 image taken with the Hubble Space Telescope on July 6, 2012

| type = Planetary

| epoch = J2000.0

| ra = {{RA|13|33|32.97}}

| dec = {{DEC|-65|58|26.7}}

| dist_ly = 3000

| appmag_v = 8.2, 8.5p

| size_v = 90 × 62 arcsec

| constellation = Musca

| radius_ly = ~1

| absmag_v = -

| notes = A peculiar PN with a binary in the center

| names = Spiral Planetary Nebula, Gum 47, IC 4274, He2-94, Sa2-95, PK 307-3.1

}}

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.{{Cite web |title=NGC 5189 (Mus) |url=https://www.southastrodel.com/NGC5189.htm |url-status=dead |archive-url=https://web.archive.org/web/20140114135738/https://www.southastrodel.com/NGC5189.htm |archive-date=2014-01-14 |website=Southern Astronomical Delights}} 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.{{Cite journal |last=Phillips |first=J. P. |last2=Reay |first2=N. K. |date=1983 |title=Ansae and the precession of central stars in planetary nebulae - The cases of NGC 5189 and NGC 6826 |journal=Astronomy and Astrophysics |volume=117 |pages=33–37 |bibcode=1983A&A...117...33P}}

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,{{Cite journal |last=Danehkar |first=Ashkbiz |last2=Karovska |first2=Margarita |last3=Maksym |first3=W. Peter |last4=Montez |first4=Rodolfo |date=January 2018 |title=Mapping Excitation in the Inner Regions of the Planetary Nebula NGC 5189 Using HST WFC3 Imaging |journal=The Astrophysical Journal |volume=852 |issue=2 |pages=87 |arxiv=1711.11111 |bibcode=2018ApJ...852...87D |doi=10.3847/1538-4357/aa9e8c |issn=0004-637X |s2cid=119365610 |doi-access=free}} 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.{{Cite journal |last=Manick |first=Rajeev |last2=Miszalski |first2=Brent |last3=McBride |first3=Vanessa |date=2015-04-01 |title=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★ |journal=Monthly Notices of the Royal Astronomical Society |language=en |volume=448 |issue=2 |pages=1789–1806 |arxiv=1501.03373 |bibcode=2015MNRAS.448.1789M |doi=10.1093/mnras/stv074 |issn=1365-2966 |s2cid=118600965 |doi-access=free}} NGC 5189 is estimated to be 546 parsecs{{cite simbad

| title=NGC 5189

| access-date=2012-12-21}} or 1,780 light years away from Earth. Other measurements have yielded results up to 900 parsecs (~3000 light-years).{{Cite journal |last=Sabin |first=L. |last2=Vázquez |first2=R. |last3=López |first3=J. A. |last4=García-Díaz |first4=Ma. T. |last5=Ramos-Larios |first5=G. |display-authors=4 |date=2012 |title=The filamentary Multi-Polar Planetary Nebula NGC 5189 |url=http://www.astroscu.unam.mx/rmaa/RMxAA..48-2/PDF/RMxAA..48-2_lsabin.pdf |journal=Revista Mexicana de Astronomía y Astrofísica |volume=48 |pages=165–76 |arxiv=1203.1297 |bibcode=2012RMxAA..48..165S}}