Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.arcetri.astro.it/~palla/ANDREAIMMAGINI/ISM/NGC3132.txt Дата изменения: Tue Jan 30 14:16:20 2001 Дата индексирования: Sat Dec 22 07:57:40 2007 Кодировка: Поисковые слова: coma

FOR RELEASE: 12:00 Noon (EST) November 5, 1998

PHOTO NO.: STScI-PRC98-39


A GLOWING POOL OF LIGHT

NGC 3132 is a striking example of a planetary nebula. This expanding
cloud of gas, surrounding a dying star, is known to amateur
astronomers in the southern hemisphere as the "Eight-Burst" or the
"Southern Ring" Nebula.

The name "planetary nebula" refers only to the round shape that many
of these objects show when examined through a small visual telescope.
In reality, these nebulae have little or nothing to do with planets,
but are instead huge shells of gas ejected by stars as they near the
ends of their lifetimes. NGC 3132 is nearly half a light year in
diameter, and at a distance of about 2000 light years is one of the
nearer known planetary nebulae. The gases are expanding away from the
central star at a speed of 9 miles per second.

This image, captured by NASA's Hubble Space Telescope, clearly shows
two stars near the center of the nebula, a bright white one, and an
adjacent, fainter companion to its upper right. (A third, unrelated
star lies near the edge of the nebula.) The faint partner is actually
the star that has ejected the nebula. This star is now smaller than our own
Sun, but extremely hot. The flood of ultraviolet radiation from its
surface makes the surrounding gases glow through fluorescence.
The brighter star is in an earlier stage of stellar evolution, but in
the future it will probably eject its own planetary nebula.

In the Heritage Team's rendition of the Hubble image, the colors were
chosen to represent the temperature of the gases. Blue represents the
hottest gas, which is confined to the inner region of the nebula. Red
represents the coolest gas, at the outer edge. The Hubble image also
reveals a host of filaments, including one long one that resembles a
waistband, made out of dust particles which have condensed out of the
expanding gases. The dust particles are rich in elements such as
carbon. Eons from now, these particles may be incorporated into new
stars and planets when they form from interstellar gas and dust. Our
own Sun may eject a similar planetary nebula some 6 billion years from
now.

Credit: Hubble Heritage Team (STScI/AURA/NASA)