HEAVYWEIGHT STARS LIGHT UP NEBULA NGC 6357 (STScI-PRC06-54)

FOR RELEASE: 1:30 pm (EST) December 11, 2006

PHOTO NO.: STScI-PRC06-54


HEAVYWEIGHT STARS LIGHT UP NEBULA NGC 6357

The small open star cluster Pismis 24 lies in the core of the large
emission nebula NGC 6357 in Sagittarius, about 8,000 light-years away
from Earth. Some of the stars in this cluster are extremely massive and
emit intense ultraviolet radiation. The brightest object in the picture
is designated Pismis 24-1. It was once thought to weigh as much as 200
to 300 solar masses. This would not only have made it by far the most
massive known star in the galaxy, but would have put it considerably
above the currently believed upper mass limit of about 150 solar masses
for individual stars. However, high-resolution Hubble Space Telescope
images of the star show that it is really two stars orbiting one another
(inset pictures at top right and bottom right). They are estimated to
each be 100 solar masses. The Hubble Advanced Camera for Surveys images
were taken in April 2006.

Credit: NASA, ESA, and J. Maíz Apellániz (Instituto de Astrofísica
de Andalucía, Spain)

For images and additional information about Pismis 24 on the Web, visit:
http://hubblesite.org/news/2006/54
http://www.spacetelescope.org/news/html/heic0619.html

For more information, contact:

Jesús Maíz Apellániz
Instituto de Astrofísica de Andalucía, Spain
011-34-958-230-529 (phone)
(e-mail)

Ray Villard
Space Telescope Science Institute, Baltimore, Md.
410-338-4514 (phone)
(e-mail)

Lars Lindberg Christensen
Hubble/ESA, Garching, Germany
011-49-89-3200-6306 (phone)
011-49-173-3872-621 (cell phone)
(e-mail)

The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency (ESA). The Space Telescope
Science Institute in Baltimore conducts Hubble science operations. The
Institute is operated for NASA by the Association of Universities for
Research in Astronomy, Inc., Washington.