Planetary nebula in the constellation Camelopardalis
IC 3568
Emission nebula
Planetary nebula
Image of IC 3568 based on HST data
Observation data: J2000 epoch
Right ascension
12h 33m 06s
Declination
+82° 34′ 00″
Distance
Roughly 4.5⋅103 ly
Apparent magnitude (V)
12.3
Constellation
Camelopardalis
Physical characteristics
Radius
Core: 0.2 ly
Designations
IC 3568, Perek-Kohoutek 123+34.1 (PK 123+34.1),[1] HD 109540 (central star)[2]
See also: Lists of nebulae
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.[3][4] 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.[5] 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.[6]
IC 3568 was discovered on August 31, 1900[7] 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.[8]