NGC 246

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title: "NGC 246" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["planetary-nebulae", "cetus", "ngc-objects", "caldwell-objects", "astronomical-objects-discovered-in-1785", "discoveries-by-william-herschel", "hipparcos-objects", "iras-catalogue-objects"] description: "Planetary nebula in the constellation Cetus" topic_path: "general/planetary-nebulae" source: "https://en.wikipedia.org/wiki/NGC_246" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Planetary nebula in the constellation Cetus ::

| image = [[Image:NGC 246.jpg|300px]] | caption=An infrared Spitzer Space Telescope image of NGC 246. Credit: NASA/JPL. | name = NGC 246 | type = Planetary | epoch = J2000 | ra = | dec = | dist_ly = | appmag_v = 8 / 11.8 (central star) | size_v = 3.8{{cite web | title=SEDS NGC Catalog Online | work=Results for NGC 246 | url=https://spider.seds.org/ngc/ngc.cgi?NGC+246 | access-date=2010-11-29}} | constellation = Cetus | radius_ly = 2-3{{cite web | title=NGC 246 | work=Astronomy: Stars & Planets | url=https://jumk.de/astronomie/special-stars/ngc-246.shtml | access-date=2013-01-07}} | absmag_v = | notes = | names = Skull Nebula, Pac-Man Nebula, Caldwell 56, HIP 3678, PMN J0047-1152, 2E 178, PN VV 4, IRAS 00445-1207, MCT 0044-1208

NGC 246 (also known as the Skull Nebula or Caldwell 56) is a planetary nebula in the constellation Cetus. It was discovered in 1785 by William Herschel. The nebula and the stars associated with it are listed in several catalogs, as summarized by the SIMBAD database.{{cite simbad | title=NGC 246 | access-date=2006-12-22}}

The nebula is roughly away. NGC 246's central star is the 12th magnitude white dwarf HIP 3678 A. In 2014, astronomers discovered a second companion to NGC 246's central star, which has a comoving companion star called HIP 3678 B. The second companion star, a red dwarf known as HIP 3678 C, was discovered using the European Southern Observatory's Very Large Telescope. This makes NGC 246 the first planetary nebula to have a hierarchical triple star system at its center. It is currently the only known example of a planetary nebula with more than two central stars.

NGC 246 is not to be confused with the Rosette Nebula (NGC 2237), which is also referred to as the "Skull." Among some amateur astronomers, NGC 246 is known as the "Pac-Man Nebula" because of the arrangement of its central stars and the surrounding star field.

Image gallery

File:The Skull Nebula NGC246 Goran Nilsson & The Liverpool Telescope.jpg|HaRGB image of The Skull Nebula (NGC 246). Data from the Liverpool Telescope, processed by Göran Nilsson. Total exposure time 1.1 hours. File:n246s.jpg|NGC 246 acquired using the Schulman 0.8m Telescope atop Mount Lemmon, AZ. This is a full color (visual) image.

References

References

1. "The Night Sky", ''[[Astronomy Now]]'', Oct 2008.
2. Löbling, Lisa. (2018-06-01). "Sliding along the Eddington Limit—Heavy-Weight Central Stars of Planetary Nebulae". Galaxies.
3. Stephen James O'Meara, ''The Caldwell Objects'', Sky Publishing Corporation, {{ISBN. 0-933346-97-2, p 223.
4. (2014-11-01). "HIP 3678: a hierarchical triple stellar system in the centre of the planetary nebula NGC 246". Monthly Notices of the Royal Astronomical Society.
5. information@eso.org. "Stars and Skulls: new ESO image reveals eerie nebula".
6. "On the triple-star origin of the planetary nebula Sh 2-71".
7. (14 February 2018). "A hole in the heart of the Rosette Nebula".
8. David H. Levy, ''Deep Sky Objects'', Prometheus Books, 2005, {{ISBN. 1-59102-361-0, p 129.

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::