MyCn18: An Hourglass Nebula
Explanation:
The sands of time are running out for the central star
of this hourglass-shaped
planetary nebula.
With its
nuclear fuel
exhausted, this brief, spectacular, closing phase of a Sun-like
star's life occurs as its outer layers are ejected - its
core becoming a cooling, fading
white dwarf.
In 1995, astronomers used the
Hubble Space Telescope
(HST) to make a series of
images of planetary nebulae,
including
the one above.
Here, delicate rings of colorful glowing gas
(
nitrogen-red,
hydrogen-green, and
oxygen-blue) outline the tenuous walls of the "hourglass".
The unprecedented sharpness of the HST images has revealed
surprising details
of the
nebula ejection process
and may help resolve the outstanding mystery
of the
variety of complex shapes and symmetries of planetary nebulae.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
