Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.arcetri.astro.it/~palla/ANDREAIMMAGINI/ISM/Ciclo.txt Дата изменения: Tue Jan 30 13:29:21 2001 Дата индексирования: Sat Dec 22 07:41:22 2007 Кодировка: Поисковые слова: supernova

EMBARGOED UNTIL: 12:30 p.m. (CDT) / 1:30 p.m. (EDT) June 1, 1999

PHOTO NO.: STScI-PRC99-20


HUBBLE SNAPSHOT CAPTURES LIFE CYCLE OF STARS

In this stunning picture of the giant galactic nebula NGC 3603, the
crisp resolution of NASA's Hubble Space Telescope captures various
stages of the life cycle of stars in one single view.

To the upper right of center is the evolved blue supergiant called
Sher 25. The star has a unique circumstellar ring of glowing gas that
is a galactic twin to the famous ring around the supernova 1987A. The
grayish-bluish color of the ring and the bipolar outflows (blobs to the
upper right and lower left of the star) indicates the presence of
processed (chemically enriched) material.

Near the center of the view is a so-called starburst cluster dominated
by young, hot Wolf-Rayet stars and early O-type stars. A torrent of
ionizing radiation and fast stellar winds from these massive stars has
blown a large cavity around the cluster.

The most spectacular evidence for the interaction of ionizing radiation
with cold molecular-hydrogen cloud material are the giant gaseous
pillars to the right and lower left of the cluster. These pillars are
sculptured by the same physical processes as the famous pillars Hubble
photographed in the M16 Eagle Nebula.

Dark clouds at the upper right are so-called Bok globules, which are
probably in an earlier stage of star formation.

To the lower left of the cluster are two compact, tadpole-shaped
emission nebulae. Similar structures were found by Hubble in Orion,
and have been interpreted as gas and dust evaporation from possibly
protoplanetary disks (proplyds). The "proplyds" in NGC 3603 are
5 to 10 times larger in size and correspondingly also more massive.

This single view nicely illustrates the entire stellar life cycle of
stars, starting with the Bok globules and giant gaseous pillars,
followed by circumstellar disks, and progressing to evolved massive stars
in the young starburst cluster. The blue supergiant with its ring and
bipolar outflow marks the end of the life cycle.

The color difference between the supergiant's bipolar outflow and the
diffuse interstellar medium in the giant nebula dramatically visualizes
the enrichment in heavy elements due to synthesis of heavier elements
within stars.

This true-color picture was taken on March 5, 1999 with the Wide Field
Planetary Camera 2.

This picture is being presented at the 194th Meeting of the American
Astronomical Society in Chicago.

Credit: Wolfgang Brandner (JPL/IPAC), Eva K. Grebel (Univ. Washington),
You-Hua Chu (Univ. Illinois Urbana-Champaign), and NASA