Planetary Nebula NGC 4361

NGC 4361
NGC 4361: Image taken with Spitzer Space Telescope [530]

History

This planetary nebula was discovered on February 7, 1785 by the famous German-British astronomer William Herschel using his selfmade reflecting telescope of 20 foot focal length (aperture 18.7 inch) in Slough near Windsor in Great Britain. He classified it as cataloged it as I 65 (class I = bright nebulae) and noted: «very bright, pretty large, irregular round, brighter in the middle, like 2 nuclei». [463] His son John cataloged the nebula in 1833 as h 1231 and first thought to be a globular cluster. He noted: «very bright, large, round very suddenly much brighter in the middle to nucleus = * 11m 90" diameter. Resolvable with power 320, and is no doubt a globular cluster; fades away to nothing.» [466] Lord Rosse observed it on April 10, 1852 and could not resolve it. [486] In his 1864 appeared «General Catalogue» John Herschel listed it as GC 2917 and still listed it as «resolvable» [467] On April 23 1868 John Herschel observed the object with a spectroscope and recognized it as nebula. He noted: «Seen at once; bright; all three lines easily seen, and a fourth suspected, at intervals 1; 3; 10 ? from the first by estimation.» [528] Dreyer added it in 1888 as NGC 4361, still describing it as «resolvable». [313]

As one can see from the Spitzer Space Telescope image (Fig. 1) there are many little foreground or background stars superimposed on the planetary nebulas disk. This probably lead to the early confusion with a globular cluster.

Physical Properties

The planetary nebula NGC 4361 was classified as a multiple-shell PN having irregular structures in the surrounding shell. The nearly spherical shell is relatively fainter than the inner regions of the nebula. A large majority of the line profiles show centroidal asymmetry that flips over two distinct axes. The presence of the two symmetry axes is interpreted as evidence for quadrupolar flows that can be produced by a precessing equatorial disk. [529] Central star is a Wolf-Rayet star of spectral class WC. Estimated distances range from 887 pc to 1035 pc [145] The evolutionary age of this PN is estimated to just circa 8000 years. [159]

«Strasbourg-ESO Catalogue of Galactic Planetary Nebulae» Acker et al., 1992 [141]
DesignationsPN G294.1+43.6: NGC 4361, PK 294+43.1, ARO 26, ESO 573-19, VV 62, VV' 110
Right Ascension (J2000.0)12h 24m 32s
Declination (J2000.0)-18° 47' 10"
Dimensions 63." (optical)
Distance 1.2 kpc
Radial Velocity+9.0 km/s ± 2.0 km/s
Expansion Velocity 32.0 km/s (O-III)
C-Star DesignationsAG82 145, BD -17 3614, GCRV 7449, HD 107969
C-Star Magnitude11.53 mag (U filter), 12.85 mag (B filter), 13.21 mag (V filter)
C-Star Spectral TypeO(H)
DiscovererHERSCHEL 1868

Finder Chart

The planetary nebula NGC 4361 is located in the constellation Corvus. The best time for observation is in the months January through May.

Corvus: NGC 4361
Chart NGC 4361
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
159«Planetary Nebulae distances in Gaia DR2» S. Kimeswenger and D. Barría; A&A Volume 616, August 2018; DOI:10.1051/0004-6361/201833647
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
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
466«Observations of nebulæ and clusters of stars, made at Slough, with a twenty-feet reflector, between the years 1825 and 1833» John Frederick William Herschel, Philosophical Transactions of the Royal Society of London, 1 January 1833, Pages: 359-505; DOI:10.1098/rstl.1833.0021
467«Catalogue of nebulae and clusters of stars» John Frederick William Herschel, Philosophical Transactions of the Royal Society of London, 1 January 1864; DOI:10.1098/rstl.1864.0001
486«On the construction of specula of six-feet aperture; and a selection from the observations of nebulæ made with them» William Parsons; Philosophical Transactions of the Royal Society of London, Volume 151, published 1 January 1861; DOI:10.1098/rstl.1861.0029
528«Results of examination of southern nebulae with the spectroscope» John Herschel, Proceedings of the Royal Society of London, 1 January 1868; DOI:10.1098/rspl.1867.0101
529«A Spatiokinematic Study of the Planetary Nebula NGC 4361: Evidence for Quadrupolar Flows» C. Muthu and B. G. Anandarao; The Astronomical Journal, Volume 121, Number 4, 2001; DOI:10.1086/319939
530Planetary Nebula NGC 4361; spitzer.caltech.edu/image/ssc2009-15a3-planetary-nebula-ngc-4361 (2022-07-21)