NGC 7026 - "Gomez' Hamburger"
In the northern part of the constellation Cygnus lies NGC 7026, which is also called "Gomez's Hamburger" because of its shape. The object
was discovered by Sherburne Burnham on June 6, 1873.
With an assumed age of less than 1,000 years, the PN is very young. Its bipolar structure can be easily recognized by the opposite bulges,
which start from an inner ring. X-ray emissions were found in these bulges by "Chandra", which were then studied in more detail with
"XMM- Newton". Hot plasma with temperatures up to 1.1 million Kelvin was found to be responsible for the diffuse X-ray emission.
With a long axis of 40" (arc seconds) and a distance of 6,000 light years, the true diameter of NGC 7026 is about 1.2 light years.
The central star is, as usual for planetary nebulae, a white dwarf with an apparent visual magnitude of about 15.1mag. It is a hydrogen-
poor "WC-star", consisting of 70% helium, 20% carbon and 10% oxygen. The core mass is estimated to be 0.56 solar masses at a surface
temperature of 80,000 Kelvin. From this, the total luminosity of the white dwarf is calculated to be 2,100 solar luminosities. Quite a lot
for such a tiny star. Due to the high temperature, most of the energy is emitted in the UV band. Using the apparent visual brightness and
the distance, the total visual luminosity is 3 times that of the sun. But even that would make the day on Earth seem pretty bright!
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In my 20 inch telescope "Gomez' Hamburger" is definitely one of the most interesting objects of its kind. At a magnification of 120x,
the PN appears distinctly greenish, while the bright star next to it appears yellowish, giving a great color contrast.
The shape of the PN comes out best at a magnification of 380x. At first glance, two elongated bars are visible, both containing a bright
knot. Two more nodes (though much fainter) are located in the northern part of the PN and south of the eastern bar. The halo tapers off
gently, especially to the north and south, where it is also very faint.
The central star was not visible. It needs a bit more aperture ;)
