NGC 7008 - Fetus Nebula
The planetary nebula NGC 7008 is also known as "Fetus Nebula" and is located in the northern part of the constellation Cygnus near the border to the constellation
Cepheus. Due to its declination of +54° it can be observed in Germany directly in the zenith. The PN was discovered in 1787 by F.W. Herschel with his 18.7"
reflector.
The apparent magnitude of NGC 7008 is 10.7mag and the apparent size was determined to 1.4'x1.1' (arcminutes). This makes the PN accessible even to smaller
telescopes.
According to the latest measurements the distance is 3.150 lightyears. Furthermore the radial velocity could be determined, which shows a value of -72km/s after
the third GAIA- release (DR3); so the planetary nebula is moving towards us. The fetus nebula was formed 5,700 years ago, so it is relatively young. The envelope
has a diameter of 0.97 light-years and an ionized mass of 0.08 solar masses. In addition, the PN emits strong X-ray emissions.
The central star has a mass of 0.55 solar masses and a surface temperature of 97,000 Kelvin. Despite its small size it shines 1,300x as bright as our Sun and reaches
an apparent magnitude of 13.9mag. It could be a very close double star with the companion 0.4" away and 0.5mag fainter.
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In a telescope with 20 inch aperture NGC 7008 offers an extremely exciting view. At first glance, many structures are visible at 270x in combination with a nebula
filter. First of all there is the ring which is opened to the east. It is neither circular nor oval but has a very peculiar shape. The northern and southern areas appear
brighter, in the north you can also see an elongated condensation, which makes the ring appear brightest at this point. Outside, i.e. in the halo of the PN, two more
faint nebular knots can be seen in the north and west. In addition, a total of three stars are visible in the nebula - one of which appears to be the central star, at least
the position of the star suggests this.
Just south of the Fetus Nebula is a rather nice looking, wide double star.
