صورة اليوم الفلکیة
Image Credit & Copyright:
NASA,
ESA,
Hubble,
HLA;
Processing & Copyright:
Harshwardhan Pathak
Explanation:
Do you see the hourglass shape -- or does it see you?
If you can picture it, the rings of
MyCn 18 trace the outline of an hourglass -- although one with an unusual eye in its center.
Either way, 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 featured here.
Pictured, 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 Hubble images has revealed
surprising details of the nebula ejection process that are helping to resolve
the outstanding mysteries
of the complex shapes and symmetries of planetary nebulas like MyCn 18.