Explanation:
Exploring
the myriad shapes found in the
cosmic zoo of
planetary
nebulae, some astronomers have focused on the
intriguing example of M2-9.
About 2,100 light-years away and over one light-year across,
M2-9
is known as a twin jet or
butterfly nebula in reference to its
striking
bipolar symmetry.
Monitoring
M2-9 over many years from ground based telescopes
has revealed the dramatic west to east (left to right)
progression of features illustrated in this collage.
The apparent motion could well be caused by an energetic
rotating beam sweeping across the nebular material.
Astronomers argue
that the beam is collimated by interacting
stellar winds in a double star system at the center of M2-9.
The binary system of a
giant star and hot white dwarf
star orbit each
other about once every 120 years.
Click on the image to watch an animated gif of M2-9.
