Abell 7

Abell 7 is a faint planetary nebula located 1800 light-years away in the constellation of Lepus. It has a generally spherical shape about 8 light-years in diameter. Within the sphere are complex details that are brought out by narrowband filters. Abell 7 is estimated to be only 20,000 years old, but the central star, a fading white dwarf, is estimated to be some 10 billion years old.[3][4][5]

Abell 7
Emission nebula
Planetary nebula
Observation data: J2000 epoch
Right ascension 05h 03m 07.53s[1][2]
Declination−15° 36′ 22.7″[1][2]
Distance1.8 kly (0.55 kpc) ly
Apparent magnitude (V)Integrated: 12.2–14.3;[3] Cental star: 15.4[2]
Apparent dimensions (V)12′.733 × 12′.733[1][2]
ConstellationLepus
Physical characteristics
Radius8 ly (2.5 pc) ly
Notable featuresSimple spherical shape
DesignationsPK 215-30.1, PN G 215.5-30.8

References
  1. SIMBAD (4 August 2014), Results for PN A66 07, SIMBAD, Centre de Données Astronomiques de Strasbourg
  2. "The Complete Abell Catalog of Planetary Nebulae". Astronomy Mall. Retrieved 2014-08-04. MAG1 = Integrated VMag of PN / MAG2 = Mag of Central Star / SIZE = Diameter in arcminutes — ABELL:07 CON: LEP PNG# / OTHER: 215.5-30.8 MAG1: 13.2 MAG2: 15.4 SIZE: 12.7 RA: 05 03 07.5 DEC: -15 36 23 URA2: 137
  3. Abell, George O. (April 1966), "Properties of Some Old Planetary Nebulae", Astrophysical Journal, 144: 259, Bibcode:1966ApJ...144..259A, doi:10.1086/148602
  4. APOD (5 December 2013), Robert J. Nemiroff (MTU); Jerry Bonnell (USRA) (eds.), Abell 7, NASA, Very faint planetary nebula Abell 7 is some 1,800 light-years distant, just south of Orion in planet Earth's skies in the constellation Lepus, The Hare. Surrounded by Milky Way stars and near the line-of-sight to distant background galaxies, its generally simple spherical shape, about 8 light-years in diameter, is outlined in this deep telescopic image. ... Abell 7 itself is estimated to be 20,000 years old. Its central star is seen here as a fading white dwarf some 10 billion years old.
  5. Abell, George O. (1955), "Globular Clusters and Planetary Nebulae Discovered on the National Geographic Society-Palomar Observatory Sky Survey", Publications of the Astronomical Society of the Pacific, 67 (397): 258, Bibcode:1955PASP...67..258A, doi:10.1086/126815
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