The sands of time are running out for the central star of this hourglass-shaped planetary nebula [ http://fusedweb.ppp…Chart_Pages/5.Plasma s/Nebula/Planetary.h tml ]. With its nuclear fuel [ http://fusedweb.ppp…] exhausted, this brief, spectacular, closing phase of a Sun-like star's life [ http://www.astro.vi…] occurs as its outer layers are ejected - its core becoming a cooling, fading white dwarf [ http://antwrp.gsfc.…]. In 1995, astronomers used the Hubble Space Telescope [ http://antwrp.gsfc.…] (HST) to make a series of images of planetary nebulae [ http://antwrp.gsfc.…], including the one above [ http://www.stsci.ed…]. Here, delicate rings of colorful glowing gas (nitrogen [ http://pearl1.lanl.…]-red, hydrogen [ http://pearl1.lanl.…]-green, and oxygen [ http://pearl1.lanl.…]-blue) outline the tenuous walls of the "hourglass". The unprecedented sharpness of the HST images has revealed surprising details [ http://www.stsci.ed…] of the nebula ejection process [ http://antwrp.gsfc.…] and may help resolve the outstanding mystery of the variety of complex shapes and symmetries of planetary nebulae [ http://www.astro.wa…].
Explanation
The sands of time are running out for the central star of this hourglass-shaped planetary nebula [ http://fusedweb.ppp…Chart_Pages/5.Plasma s/Nebula/Planetary.h tml ]. With its nuclear fuel [ http://fusedweb.ppp…] exhausted, this brief, spectacular, closing phase of a Sun-like star's life [ http://www.astro.vi…] occurs as its outer layers are ejected - its core becoming a cooling, fading white dwarf [ http://antwrp.gsfc.…]. In 1995, astronomers used the Hubble Space Telescope [ http://antwrp.gsfc.…] (HST) to make a series of images of planetary nebulae [ http://antwrp.gsfc.…], including the one above [ http://www.stsci.ed…]. Here, delicate rings of colorful glowing gas (nitrogen [ http://pearl1.lanl.…]-red, hydrogen [ http://pearl1.lanl.…]-green, and oxygen [ http://pearl1.lanl.…]-blue) outline the tenuous walls of the "hourglass". The unprecedented sharpness of the HST images has revealed surprising details [ http://www.stsci.ed…] of the nebula ejection process [ http://antwrp.gsfc.…] and may help resolve the outstanding mystery of the variety of complex shapes and symmetries of planetary nebulae [ http://www.astro.wa…].
