Planetary nebula in the constellation Scorpius
NGC 6337, the Ghostly Cheerio or Cheerio Nebula, is a toroidal planetary nebula in the constellation Scorpius. It appears as a ring-shaped (annular) transparent nebula resembling a piece of the breakfast cereal Cheerios, hence the name. Filament and knots, and a faint shell surround the ring.[2] Its magnitude is 11.90; its position in Scorpius is right ascension 17h 22m15.67s, declination -38° 29' 01.73".[1] The Ghostly Cheerio has a redshift value of -0.000236.
There is convincing evidence that a binary nucleus exists at the center of the nebula,[3] with masses of 0.6 and 0.3 M⊙, and a separation of ≤ 1.26 R⊙, indicating a probable common envelope phase. The Ghostly Cheerio's projected radial expansion is slow, averaging 1–2 kilometres per second (0.6–1.2 mi/s).[2]
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