IC 3568 is a planetary nebula that is 1.3 kiloparsecs (4500 ly) away from Earth in the constellation of Camelopardalis (just 7.5 degrees from Polaris). It is a relatively young nebula and has a core diameter of only about 0.4 light years. It was dubbed the Lemon Slice Nebula by Jim Kaler, due to its appearance in one false-colour image from the Hubble Space Telescope.[1] [2] The Lemon Slice Nebula is one of the most simple nebulae known, with an almost perfectly spherical morphology. The core of the nebula does not have a distinctly visible structure in formation and is mostly composed of ionized helium.[3] A faint halo of interstellar dust surrounds the nebula. The central star of the planetary nebula is an O-type star with a spectral type of O(H)3.[4]
IC 3568 was discovered on August 31, 1900[5] by the American astronomer Robert Grant Aitken while using Lick Observatory's 12" Clark Refractor. While examining Comet Borrelly-Brooks, he found that the star BD +83° 357 in Camelopardalis is surrounded by a small circular nebula. This was confirmed with the observatory's 36" Refractor the next night. IC 3568 was misclassified as a compact galaxy in the Uppsala General Catalogue, as UGC 7731.[6]