Tonight's Sky
Sun
Sun
Moon
Moon
Mercury
Mercury
Venus
Venus
Mars
Mars
Jupiter
Jupiter
Saturn
Saturn

Tonight's Sky — Change location

OR

Searching...

Tonight's Sky — Select location

Tonight's Sky — Enter coordinates

° '
° '

How heavy can a star be?

Hubble reveals the extraordinary mass of Pismis 24-1 is actually divided among three stars.
Provided by STScI, Baltimore, Maryland
Emission nebula NGC 6357 harbors star cluster Pismis 24 in its center &mdash and some of the heaviest stars known.
Davide De Martin (ESA/Hubble), the ESA/ESO/NASA Photoshop FITS Liberator/ Digitized Sky Survey 2
Hubble's ACS shows Pismis 24-1 (left) is actually a tight binary. Each star weighs around 100 solar-masses.
NASA/ ESA and Jesús Maíz Apellániz (Instituto de astrofísica de Andalucía, Spain).
December 13, 2006
The small open star cluster Pismis 24 lies in the core of the large emission nebula NGC 6357 in Scorpius, 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, Hubble Space Telescope high-resolution images of the star show that it is really two stars orbiting one another. They are estimated to each be 100 solar masses.

In addition, spectroscopic observations with ground-based telescopes further reveal that one of the stars is actually a tight binary that is too compact to be resolved even by Hubble. This divides the estimated mass for Pismis 24-1 among the three stars. Although the stars are still among the heaviest known, the mass limit has not been broken thanks to the multiplicity of the system.

The observations were performed by a team of astronomers led by Jesús Maíz Apellániz of the Instituto de Astrofísica de Andalucía in Spain. The team imaged Pismis 24-1 with Hubble's Advanced Camera for Surveys in April 2006.

Star cluster Pismis 24 glows above emission nebula NGC 6357 in this image. Part of the nebula is ionized by the youngest (bluest) heavy stars in Pismis 24.
NASA/ESA/Jesús Maíz Apellániz
0

JOIN THE DISCUSSION

Read and share your comments on this article
Comment on this article
Want to leave a comment?
Only registered members of Astronomy.com are allowed to comment on this article. Registration is FREE and only takes a couple minutes.

Login or Register now.
0 comments
ADVERTISEMENT

FREE EMAIL NEWSLETTER

Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter.

ADVERTISEMENT
ADVERTISEMENT
BoxProductcovernov

Click here to receive a FREE e-Guide exclusively from Astronomy magazine.

Find us on Facebook

Loading...