False color image of the bright central region of IC 3568. This is the image that gave the nebula its common name.

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]

See also

  • NGC 40 (the Bow-Tie Nebula in Cepheus)

References

  1. ^ The Deep Sky Field Guide to Uranometria 2000.0, Chart 9 (Murray Cragin, James Lucyk, Barry Rappaport), Willmann-Bell, 1993
  2. ^ Sky Catalogue 2000.0, Volume 2: Double Stars, Variable Stars and Nonstellar Objects (edited by Alan Hirshfeld and Roger W. Sinnott, 1985), page 308
  3. ^ IC 3568
  4. ^ Portal to the Universe.org
  5. ^ "starrycritters.com". Archived from the original on 2015-04-02. Retrieved 2013-07-29.
  6. ^ González-Santamaría, I.; Manteiga, M.; Manchado, A.; Ulla, A.; Dafonte, C.; López Varela, P. (2021). "Planetary nebulae in Gaia EDR3: Central star identification, properties, and binarity". Astronomy & Astrophysics. 656: A51. arXiv:2109.12114. Bibcode:2021A&A...656A..51G. doi:10.1051/0004-6361/202141916. S2CID 237940344.
  7. ^ Courtney Seligman: Closeup on IC 3568, the Lemon Slice Nebula
  8. ^ Wolfgang Steinicke: Lick Observatory with 36" and 12" Refractor telescopes, used by Robert Grant Aitken during the discovery of IC 3568
  • Media related to IC 3568 at Wikimedia Commons
Allikas: https://en.wikipedia.org/wiki/Lemon_Slice_Nebula
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