| 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] |
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.
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The central star of the planetary nebula is a magnitude 12.8 O-type star with a spectral type of O(H)3. It is estimated to have a mass less than the Sun, a temperature of over 50,000 K , and a bolometric luminosity of about 2,400 L☉. [6]
IC 3568 was discovered on August 31, 1900 by the American astronomer Robert Grant Aitken while using Lick Observatory's 12" Clark refractor to observe comet Borrelly-Brooks. He noticed that the "star" BD+83°357 in Camelopardalis was actually a small nebula. He used the observatory's 36" refractor the next night to confirm that this was a round nebula. [7] IC 3568 was mistakenly classified as a compact galaxy in the Uppsala General Catalogue, as UGC 7731. [8]
