Planetary Nebula NGC 6778

NGC 6778
NGC 6778: Composite color picture taken by 2.56m Nordic Optical Telescope (NOT) in La Palma, Canarias. [614]

History

This planetary nebula was first discovered by John Herschel on 21 May 1825 using his 18.3 inch reflecting telescope. In his «Slough Catalogue» of 1833 he listed it as h 2038 and noted: «An extremely small stellar nebula = a star 15m; it is 2/3 of a diameter of field (=10') from a double star which it follows to the south. Position from the star = 240° ±. The RA is excessively loose.» [466] In his «General Catalogue» of 1864 he listed it as GC 4490 and just noted: «extremely small, stellar». [467] That entry later in 1888 became NGC 6785 in Dreyers «New General Catalogue». [313]

On 25 June 1863 the German Astronomer Albert Marth looked through William Lassell's 48 inch reflector on Malta and also discovered the same nebula. He described it as «small, extended ill-defined disc». In 1888 Edward Charles Pickering classified the nebula as a planetary. [141] Later in 1888 it was listed as NGC 6778 in Dreyers «New General Catalogue». [313] Today the object is generally referred to as NGC 6778.

Physical Properties

NGC 6778 is a bipolar planetary nebula with a short orbiting (~0.15 days) binary central star. It displays two systems of fast collimated outflows with a radial velocity of ~100 km/s. The equatorial ring is highly disrupted with many radial features like filamentary wisps and cometary knots. [614] The visual magnitude is 14.8 and heliocentric distance 3.1 kpc. [145]

«Strasbourg-ESO Catalogue of Galactic Planetary Nebulae» Acker et al., 1992 [141]
Designations PN G034.5-06.7: NGC 6778, PK 34-06.1, ARO 72, Sa 2-388, VV 227, VV' 491
Right Ascension (J2000.0) 19h 18m 25s
Declination (J2000.0) -01° 35' 53"
Dimensions 15.8" (optical)
Distance 1.0 kpc
Radial Velocity +91.0 ± 3.0 km/s
Expansion Velocity 20.0 (O-III) km/s
C-Star Designations AG82 362, CSI -01 -19156, HD 180871, PLX 4502
C-Star Magnitude B: 16.91
Discoverer PICKERING 1882

Finder Chart

The planetary nebula NGC 6778 is located in the constellation Aquila, just 1.5° northeast of the brighter planetary neblua NGC 6772. You may want to find NGC 6772 first and then hop to NGC 6778. The best time to observe it is during the months of June to September.

Finder Chart Planetary Nebula NGC 6778
Planetary Nebula NGC 6778 in constellation Aquila. Charts created using SkySafari 6 Pro and STScI Digitized Sky Survey. Limiting magnitudes: Constellation chart ~6.5 mag, DSS2 close-ups ~20 mag. [149, 160]

Objects Within a Radius of 10°

References

  • [141] Strasbourg-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); Bibcode:1992secg.book.....A; cdsarc.unistra.fr/viz-bin/cat/V/84
  • [145] SIMBAD astronomical database; simbad.u-strasbg.fr/simbad
  • [149] SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
  • [160] The 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
  • [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; jstor.org/stable/108864
  • [614] «NGC 6778: a disrupted planetary nebula around a binary central star» M. A. Guerrero1 and L. F. Miranda; A&A Volume 539, March 2012; DOI:10.1051/0004-6361/201117923