Planetary Nebula Abell 72

Abell 72
Abell 72: Planetary nebula in Delphinus; 500 mm Cassegrain f=5800 mm f/11.4; SBIG STL11K; 60+10+10+10 min LRGB; Bernese Highlands; © 2005 Radek Chromik

History

The planetary nebula Abell 72 (PK 59-18.1) was discovered in 1955 by the American astronomer George Ogden Abell on the photo plates of the “Palomar Observatory Sky Survey” (POSS). In 1955 he published a first list of 13 globular clusters and the positions of 73 planetary nebulae. The PN had the number 58 (A55 59). In 1966 Abell published a complete list including the size and description of the 86 planetary nebulae discovered on the POSS photo plates. The designation PK 59-18.1 comes from the two Czechoslovak astronomers Luboš Perek and Luboš Kohoutek, who in 1967 compiled a catalog of all the planetary nebulae of the Milky Way known at the time. [331, 332]

Physical Properties

Abell 72 is very large with an angular diameter of a little more than two arc minutes, but has a low surface brightness with 16 magnitudes. This suggests an advanced age. The distance was determined to be 1151 parsecs (around 3700 light years) in 2008. [145]

«Strasbourg-ESO Catalogue of Galactic Planetary Nebulae» Acker et al., 1992 [141]
DesignationsPN G059.7-18.7: A 72, PK 59-18.1, A55 59, ARO 173, VV' 538
Right Ascension (J2000.0)20h 50m 02s
Declination (J2000.0)13° 33' 29"
Dimensions 127." (optical)
Radial Velocity-58.6 km/s ± 23.0 km/s
C-Star DesignationsAG82 414, CSI +13 -20477, UBV 18031
C-Star Magnitude14.55 mag (U filter), 15.79 mag (B filter), 16.12 mag (V filter)
C-Star Spectral TypeIUE obsns
DiscovererABELL 1955

Finder Chart

The planetary nebula Abell 72 is located in the constellation Delphinus (Dolphin). The best time to observe is May to October, when it is highest at night.

Chart Abell 72
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
331«Globular Clusters and Planetary Nebulae Discovered on the National Geographic Society-Palomar Observatory Sky Survey» Abell, G. O.; Publications of the Astronomical Society of the Pacific, Vol. 67, No. 397, p.258-261, August 1955; DOI:10.1086/126815; Bibcode:1955PASP...67..258A
332«Properties of Some Old Planetary Nebulae» Abell, G. O.; Astrophysical Journal, vol. 144, p.259, April 1966; DOI:10.1086/148602; Bibcode:1966ApJ...144..259A