THE DUMBBELL NEBULA
dying star's last hurrah is creating a flurry of
glowing knots of gas that appear to be streaking
through space in this close-up image of the Dumbbell
Nebula, taken with NASA's Hubble Space Telescope.
Dumbbell, a nearby planetary nebula residing more
than 1,200 light-years away, is the remains of a
star that has reached the end of its life in a spectacular
display of color. The nebula, also known as Messier
27 (M27), was the first planetary nebula ever discovered.
French astronomer Charles Messier spied it in 1764.
Hubble images of the Dumbbell show many knots, but
their shapes vary. Some look like fingers pointing
at the central dying star, located just off the
upper left of the image; others are isolated clouds,
with or without tails. Their sizes are typically
several times larger than the distance from the
Sun to Pluto and each contains as much mass as 3
knots are forming at the interface between the hot
(ionized) and cool (neutral) portion of the nebula.
This area of temperature differentiation moves outward
from the central star as the nebula evolves. In
the Dumbbell astronomers are seeing the knots soon
after this hot gas passes by.
knots of gas and dust seem to be a natural part
of the evolution of planetary nebulae. They form
in the early stages and their shape changes as the
nebula expands. Similar knots have been discovered
in other nearby planetary nebulae that are all part
of the same evolutionary scheme. They can be seen
in Hubble telescope photos of the Ring Nebula (NGC
6720), the Eskimo Nebula (NGC 2392) and the Retina
Nebula (IC 4406). The detection of these knots in
all the nearby planetaries imaged by the Hubble
telescope allows astronomers to hypothesize that
knots may be a feature common in all planetary nebulae.
image, created by the Hubble Heritage Team (STScI),
was taken by Hubble's Wide Field Planetary Camera
2 in November 2001, by Bob O'Dell (Vanderbilt University)
and collaborators. The filters used to create this
color image show oxygen in blue, hydrogen in green
and a combination of sulfur and nitrogen emission
Credit: NASA and the Hubble Heritage Team (STScI/AURA)
Acknowledgment: C.R. O'Dell (Vanderbilt University)