Rungs of the Red Rectangle
Credit:
H. Van Winckel (KU Leuven),
M. Cohen (UC Berkeley),
H. Bond (STScI),
T. Gull (GSFC),
ESA,
NASA
A distinctive X-shape and ladder-like rungs appear in
this Hubble Space Telescope
image of the intriguing
Red Rectangle Nebula.
The dusty cosmic cloud was originally identified as
a strong source of
infrared
radiation and is now
believed to contain icy dust grains and hydrocarbon
molecules formed in the cool outflow from an aging
central star.
So why does it look like a big X?
A likely explanation is that the
central star - actually a close pair of stars - is surrounded by
a thick dust torus which pinches the otherwise spherical
outflow into tip-touching cone shapes.
Because we view the torus edge-on, the boundary edges of
the cone shapes seem to form an X.
The distinct rungs suggest the outflow occurs in
fits and starts.
About 2,300 light-years away toward the fanciful constellation
Monoceros,
the Red Rectangle nebula should be transformed
into a glorious planetary nebula
as its cool central star becomes a
hot white dwarf over
the next few thousand years.
This sharp Hubble picture spans only about one third of a light-year
at the distance of the Red Rectangle.