Planetary nebula NGC
7662 in Andromeda
Description of NGC 7662 in
The Deep Sky Field Guide to Uranometria 2000:
Ring structure; involved in a larger
and fainter disk; irregular in form.
A bright, slightly elliptical planetary
nebula, measuring 32” x 28”, bluish-green in color. Although discernible
with very small telescopes as a nearly stellar object of magnitude 8.5
a visual observer needs a 6 inch scope and a magnification of at least
50x to see a hint of the softly glowing disc. In a 10-inch telescope the
darker center gives it an annular appearance; the central star is a difficult
object visually, but appears clearly on photographs.
The distances of the planetary nebulae
are not known with any real accuracy. According to the Skalnate Pleso Catalogue
(1951) the distance of NGC 7662 is about 1,800 light years, the actual
diameter about 20,000 AU. In a survey of the brighter planetaries, C.R.O'Dell
(1963) derived a distance of 1,740 parsecs or about 5,600 light years for
this nebula, increasing the actual size to 0.8 light year, or nearly 50,000
AU. The central star is a bluish dwarf with a continuous spectrum and a
computed temperature of about 75,000K. The nuclei of the planetary nebulae
are among the hottest stars known.
- NGC 7662
- Other ID: PK 106-17.1
- Magnitude: 9.0
- Constellation: Andromeda
- RA: 23h 25m 53.9s
- Dec: +42d 33' 00"
- Size (mins): 2.2
- Classification: Planetary
George Normandin, KAS
October 29th, 1997