History

This nebulous object was discovered in 1955 by the American astronomer George Ogden Abell on the photographic plates of the Palomar Observatory Sky Survey (POSS) and was originally thought to be a planetary nebula. In 1955, he published an initial list of 13 globular clusters and the positions of 73 planetary nebulae. In 1966, Abell then published a complete list, on which the object was listed as number 64. ^{[331, 332]}

The two Czechoslovak astronomers Luboš Perek and Luboš Kohoutek compiled a catalog in 1967 of all planetary nebulae in the Milky Way known at that time, listing Abell 64 under the designation PK 44-9.1. The «Catalogue of Principal Galaxies» from 1989 lists the galaxy CGCG 397-5 from the Zwicky Catalog at this position under PGC 63630, while in the «Strasbourg-ESO Catalogue of Galactic Planetary Nebulae» from 1992, Abell 64 is still classified as a «possible PN». ^[146]

Physical Properties

Abell 64 is not a planetary nebula. It is an unusual formed galaxy at a distance of 53.46 Mpc. ^[145]