NGC 7009, Saturn Nebula

NGC 7009
NGC 7009: Image taken with the ESO VLT telescope in Chile [229]

History

This planetary nebula was discovered on September 7, 1782 by Wilhelm Herschel with his small 6.2 inch reflecting telescope. He entered it as IV 1, where class «IV» applied to his visual classification for planetary nebulae, to which he also included unusual shapes such as «stars with burs, with milky chevelure, with short rays, remarkable shapes, etc.» He described the PN as a «very bright, nearly round planetary, not well defined disk». [463] NGC 7009 was later nicknamed the «Saturn Nebula» by Lord Rosse because of its elongated shape, reminiscent of Saturn's rings. [196] The PN was given the designation NGC 7009 by John L. E. Dreyer in his «New General Catalogue of Nebulae and Clusters of Stars» published in 1888. [313]

Physical Properties

NGC 7009
NGC 7009: HST image and schematic representation of the structure [234]

At Simbad one finds a distance of 1325 pc for NGC 7009. [145] Originally, the star had less than eight solar masses and shed its envelopes into space. The central star is now a hot white dwarf with an apparent magnitude of about 11.5, which causes the nebula's gas to glow green with its strong UV radiation. [234]

«Strasbourg-ESO Catalogue of Galactic Planetary Nebulae» Acker et al., 1992 [141]
DesignationsPN G037.7-34.5: NGC 7009, PK 37-34.1, ARO 16, VV 259, VV' 541, EM* CDS 1211
Right Ascension (J2000.0)21h 04m 11s
Declination (J2000.0)-11° 21' 57"
Dimensions 28.5" (optical)
Distance 0.60 kpc
Radial Velocity-44.0 km/s ± 3.0 km/s
Expansion Velocity 20.6 km/s (O-III), 20.0 km/s (N-II)
C-Star DesignationsAG82 419, BD -11 5511, GCRV 13233, HD 200516, TD1 27614
C-Star Magnitude12.66 mag (B filter), 12.78 mag (V filter)
C-Star Spectral TypeO(H)
DiscovererHERSCHEL 1782

Finder Chart

The Saturn Nebula is located in the constellation Aquarius, north of Capricornus (Capricornus). The best observation time is August to October.

Chart NGC 7009
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

References

141Strasbourg-ESO Catalogue of Galactic Planetary Nebulae; A. Acker, F. Ochsenbein, B. Stenholm, R. Tylenda, J. Marcout, C. Schohn; European Southern Observatory; ISBN 3-923524-41-2 (1992); cdsarc.unistra.fr/viz-bin/cat/V/84 (2021-02-18)
145SIMBAD astronomical database; simbad.u-strasbg.fr/simbad
149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
196Celestial Atlas by Curtney Seligman; cseligman.com/text/atlas.htm (2020-12-28)
229MUSE image of the Saturn Nebula; eso.org/public/images/eso1731a (2021-01-17)
234NGC 7009 illustration; esahubble.org/images/opo9738m (2021-01-19)
313«A New General Catalogue of Nebulae and Clusters of Stars, being the Catalogue of the late Sir John F.W. Herschel, Bart., revised, corrected, and enlarged» Dreyer, J. L. E. (1888); Memoirs of the Royal Astronomical Society. 49: 1–237; Bibcode:1888MmRAS..49....1D
463«Catalogue of one thousand new nebulae and clusters of stars» William Herschel, Philosophical Transactions of the Royal Society of London, 1 January 1786; DOI:10.1098/rstl.1786.0027