M2-9: Wings of a Butterfly Nebula
Are stars better appreciated for their art after they die?
Actually, stars usually create their most artistic displays as they die.
In the case of low-mass stars like our
Sun and
M2-9 pictured above,
the stars transform themselves from normal stars to
white dwarfs
by casting off their outer gaseous envelopes.
The expended gas frequently forms an impressive display called a
planetary nebula that fades gradually over thousand of years. M2-9, a butterfly planetary nebula 2100 light-years away shown in
representative colors,
has wings that tell a strange but
incomplete tale. In the center, two stars orbit inside a
gaseous disk 10 times the orbit of
Pluto.
The expelled envelope of the dying star breaks out from the
disk creating the
bipolar appearance.
Much remains unknown about the physical processes that cause
planetary nebulae.