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NGC 6857

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NGC 6857
Nebula
Observation data: J2000 epoch
Right ascension20h 01m 53s
Declination+33° 29′ 26″
Distance6700[1] pc
Apparent magnitude (V)11.4
Apparent dimensions (V)0.63' x 0.63'[2]
ConstellationCygnus
DesignationsGC 4536, h 2062, Sh 2-99, Sh 2-100, PGC 3517682
See also: Lists of nebulae

NGC 6857 is an emission nebula and star-forming region[3] located in the constellation Cygnus. It is located in the Perseus Arm of the Milky Way galaxy.[4]

It was discovered by William Herschel on 6 September 1784. It was later observed by John Herschel, who believed it to be a star cluster. He described it as "A small bunch of very minute Milky Way stars, so small as almost to look nebulous; north preceding is another." Rudolph Minkowski would conclude in 1946 that NGC 6857 was a nebula.

The nebula is divided into two parts. The two parts are designated at Sh 2-99 and Sh 2-100.[5] It visually resembles a planetary nebula.[6]

Despite not being a galaxy, a PGC number was assigned to it by HyperLEDA.[7]

References

[edit]
  1. ^ Forbes, D. "Photometry and spectroscopy of stars in northern H II regions".
  2. ^ "NGC 6857 - HII Ionized region in Cygnus".
  3. ^ "Sh 2-99".
  4. ^ "Sh 2-100".
  5. ^ "Galactic Nebulae NGC 6857 (Sh 2-100) + Sh 2-99".
  6. ^ "NOTES FROM OBSERVATION II. NGC 6857".
  7. ^ "Celestial Atlas NGC Objects: NGC 6850 - 6899".