Planetary Nebula Abell 79

Abell 79
Abell 79: Planetary nebula in Lacerta; 500 mm Cassegrain f=5800 mm f/11.4; SBIG STL11K; 60+60+60+60 min LRGB; Bernese Highlands; © 2005 Radek Chromik

History

The planetary nebula Abell 79 (PN A55 65, PN A66 79, PK 102-2.1) was discovered in 1955 by the American astronomer George Ogden Abell on the photo plates of the Palomar Observatory Sky Survey (POSS). In 1966 he published a list of a total of 86 planetary nebulae discovered on the POSS photo plates. [331, 332]

Physical Properties

Abell 79
Abell 79: Planetary nebula in Lacerta; Takahashi Mewlon 250 CR, (f=2500 mm / f10), SBIG ST-8300; 14L x 1200 sec 1×1, 15R, 10G, 13B, 8HA 2×2 x 1200 sec; Bernese Highlands; © 2016 Bernhard Blank, Dragan Mihajlovic

Abell 79 is an unusually shaped planetary nebula. It consists of an irregular and widened oval ring from which weak, oppositely directed lobes emerge, which have almost disappeared in the interstellar medium. A pronounced asymmetry can be seen in the surface brightness of the northern lobe: the northeast side is much brighter than the other. The presumably circular ring is inclined at 49 degrees with the north side in our direction. Strangely enough, the central star is a relatively cool dwarf star that is unable to produce the ionizing radiation visible in its spectrum, which suggests an invisible, hot companion. [207]

The distance to Abell 79 is 1801 parsecs, about 5900 light years. Apparent brightnesses measured in different filters: B 17.8 mag, V: 16.9 mag, R: 16.3 mag, I: 15.7 mag, J: 15.0 mag, H: 14.6 mag, K: 14.4 mag. [145]

«Strasbourg-ESO Catalogue of Galactic Planetary Nebulae» Acker et al., 1992 [141]
DesignationsPN G102.9-02.3: A 79, PK 102-02.1, A55 65, ARO 372, VV' 562
Right Ascension (J2000.0)22h 26m 18s
Declination (J2000.0)54° 49' 41"
Dimensions 54." (optical)
Expansion Velocity 12.5 km/s (O-III), 12.5 km/s (N-II)
C-Star DesignationsAG82 440
C-Star Magnitude18.7 mag (B filter)
DiscovererABELL 1955

Finder Chart

The planetary nebula Abell 79 is located in the constellation Lacerta (Lizard). It is circumpolar in Central Europe, but the best time to observe it is May to December, when it is highest at night.

Chart Abell 79
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
207Editor's choice: Abell 79 by Hal Heaton, June 12, 2018; skyandtelescope.org/online-gallery/abell-79 (2021-05-11)
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