NASA Astronomy Picture of the Day Collection

MyCn18: An Hourglass Nebula

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://plabpc.csust…] occurs as its outer layers are ejected - its core becoming a cooling, fading White Dwarf [ http://antwrp.gsfc.…]. Astronomers have recently 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-red, hydrogen-green, and oxygen-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://antwrp.gsfc.…].

R. Sahai and J. Trauger (JPL [ http://www.jpl.nasa…]), WFPC2 Science Team [ http://astro.nmsu.e…], NASA [ http://www.nasa.gov/],

Goddard Space Flight Center (GSFC)

Jet Propulsion Laboratory (JPL)

Sun

nebula

Hubble Space Telescope (HST)

http://antwrp.gsfc.…

SPD-APOD-ap960118