HFG1 & Abell 6: Planetary Nebulae
Planetary nebulae like
Heckathorn-Fesen-Gull 1 (HFG1) and
Abell 6 in the constellation
Cassiopeia are remnants from the last phase of a
medium sized star like our
Sun.
In spite of their shapes, planetary nebulae have
nothing in common with actual planets.
Located in the bottom left part of the
featured photo, HFG1 was created by the
binary star system V664 Cas, which consists of a
white dwarf star and a
red giant star.
Both stars orbit their
center of mass over about
half an Earth day.
Traveling with the entire nebula at a speed about 300 times
faster than the fastest train on Earth, V664 Cas generates a
bluish arc shaped
shock wave.
The wave interacts most strongly with the surrounding
interstellar medium in the areas where the arc is brightest.
After roughly
10,000 years, planetary nebulae become invisible due to a lack of
ultraviolet light being emitted by the
stars that create them.
Displaying
beautiful shapes and structures,
planetary nebulae are
highly desired objects for astrophotographers.