Astronomy:NGC 6857
From HandWiki
| Emission nebula | |
|---|---|
| H II region | |
 | |
| Observation data: J2000 epoch | |
| Right ascension | 20h 01m 53s |
| Declination | +33° 29′ 26″ |
| Distance | 6700[1] pc |
| Apparent magnitude (V) | 11.4 |
| Apparent dimensions (V) | 0.63' x 0.63'[2] |
| Constellation | Cygnus |
| Designations | GC 4536, h 2062, Sh 2-99, Sh 2-100, PGC 3517682 |
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
- ↑ Forbes, D.. "Photometry and spectroscopy of stars in northern H II regions". https://ui.adsabs.harvard.edu/abs/1989A%26AS...77..439F/abstract.
- ↑ "NGC 6857 - HII Ionized region in Cygnus". https://theskylive.com/sky/deepsky/ngc6857-object.
- ↑ "Sh 2-99". http://galaxymap.org/cat/view/sharpless/99.
- ↑ "Sh 2-100". http://galaxymap.org/cat/view/sharpless/100.
- ↑ "Galactic Nebulae NGC 6857 (Sh 2-100) + Sh 2-99". https://www.deepskycorner.ch/obj/ngc6857.en.php.
- ↑ "NOTES FROM OBSERVATION II. NGC 6857". https://iopscience.iop.org/article/10.1086/128986/pdf.
- ↑ "Celestial Atlas NGC Objects: NGC 6850 - 6899". https://cseligman.com/text/atlas/ngc68a.htm.
Template:NGC objects: 6001-7000
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