Andrew Yee
May 16th 06, 03:14 AM
Harvard-Smithsonian Center for Astrophysics
60 Garden Street, Cambridge, MA 02138 USA
Phone: 617.496.7941 Fax: 617.495.7356
May 10, 2006
Mz 3, BD+30-3639, Hen 3-1475, and NGC 7027:
Planetary Nebulas -- Fast Winds from Dying Stars
[http://chandra.harvard.edu/photo/2006/pne/]
This panel of composite images shows part of the unfolding drama of the last
stages of the evolution of sun-like stars. Dynamic elongated clouds envelop
bubbles of multimillion degree gas produced by high-velocity winds from
dying stars. In these images, Chandra's X-ray data are shown in blue, while
green and red are optical and infrared data from Hubble.
Planetary nebulas -- so called because some of them resemble a planet when
viewed through a small telescope -- are produced in the late stages of a
sun-like star's life. After several billion years of stable existence (the
sun is 4.5 billion years old and will not enter this phase for about 5
billion more years) a normal star will expand enormously to become a bloated
red giant. Over a period of a few hundred thousand years, much of the star's
mass is expelled at a relatively slow speed of about 50,000 miles per hour.
This mass loss creates a more or less spherical cloud around the star and
eventually uncovers the star's blazing hot core. Intense ultraviolet
radiation from the core heats the circumstellar gas to ten thousand degrees,
and the velocity of the gas flowing away from the star jumps to about a
million miles per hour.
This high speed wind appears to be concentrated into opposing supersonic
funnels, and produces the elongated shapes in the early development of
planetary nebulas (BD+30-3639 appears spherical, but other observations
indicate that it is viewed along the pole.) Shock waves generated by the
collision of the high-speed gas with the surrounding cloud create the hot
bubbles observed by Chandra. The origin of the funnel-shaped winds is not
understood. It may be related to strong, twisted magnetic fields near the
hot stellar core.
60 Garden Street, Cambridge, MA 02138 USA
Phone: 617.496.7941 Fax: 617.495.7356
May 10, 2006
Mz 3, BD+30-3639, Hen 3-1475, and NGC 7027:
Planetary Nebulas -- Fast Winds from Dying Stars
[http://chandra.harvard.edu/photo/2006/pne/]
This panel of composite images shows part of the unfolding drama of the last
stages of the evolution of sun-like stars. Dynamic elongated clouds envelop
bubbles of multimillion degree gas produced by high-velocity winds from
dying stars. In these images, Chandra's X-ray data are shown in blue, while
green and red are optical and infrared data from Hubble.
Planetary nebulas -- so called because some of them resemble a planet when
viewed through a small telescope -- are produced in the late stages of a
sun-like star's life. After several billion years of stable existence (the
sun is 4.5 billion years old and will not enter this phase for about 5
billion more years) a normal star will expand enormously to become a bloated
red giant. Over a period of a few hundred thousand years, much of the star's
mass is expelled at a relatively slow speed of about 50,000 miles per hour.
This mass loss creates a more or less spherical cloud around the star and
eventually uncovers the star's blazing hot core. Intense ultraviolet
radiation from the core heats the circumstellar gas to ten thousand degrees,
and the velocity of the gas flowing away from the star jumps to about a
million miles per hour.
This high speed wind appears to be concentrated into opposing supersonic
funnels, and produces the elongated shapes in the early development of
planetary nebulas (BD+30-3639 appears spherical, but other observations
indicate that it is viewed along the pole.) Shock waves generated by the
collision of the high-speed gas with the surrounding cloud create the hot
bubbles observed by Chandra. The origin of the funnel-shaped winds is not
understood. It may be related to strong, twisted magnetic fields near the
hot stellar core.