MyCn18: An Hourglass Planetary Nebula
From NASA’s Astronomy
Picture of the Day
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 that are helping to resolve the
outstanding mysteries of the complex shapes
and symmetries of planetary nebulas.
