Far Out
- Pismis 24, a star cluster located 8,000 light-years from Earth, was initially thought to be a single massive star.
- The star’s mass was estimated to be around 200-300 solar masses, making it potentially the most massive known star in the galaxy.
- However, measurements taken by NASA’s Hubble Space Telescope revealed that Pismis 24-1 is actually two separate stars.
- This discovery halved the total mass of the system to around 100-150 solar masses each.
- The finding provides new insights into the upper mass limit for individual stars in our galaxy, which was previously believed to be around 150 solar masses.
Pismis 24, the star cluster seen here in an image released on Dec. 11, 2006, lies within the much larger emission nebula called NGC 6357, located about 8,000 light-years from Earth. The brightest object in the picture was once thought to be a single star with an incredibly large mass of 200 to 300 solar masses. That would have made it by far the most massive known star in the galaxy and would have put it considerably above the currently believed upper mass limit of about 150 solar masses for individual stars. Measurements from NASA’s Hubble Space Telescope, however, discovered that Pismis 24-1 is actually two separate stars, and, in doing so, “halved” their mass to around 100-150 solar masses each.
Image credit: NASA, ESA and Jesús Maíz Apellániz (Instituto de Astrofísica de Andalucía, Spain); Acknowledgment: Davide De Martin (ESA/Hubble)
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Q. What is Pismis 24?
A. The star cluster seen in an image released on Dec. 11, 2006.
Q. Where is Pismis 24 located?
A. It lies within the emission nebula called NGC 6357, approximately 8,000 light-years from Earth.
Q. What was initially thought to be the brightest object in the picture of Pismis 24?
A. A single star with an incredibly large mass of 200 to 300 solar masses.
Q. How did NASA’s Hubble Space Telescope discover that Pismis 24-1 is actually two separate stars?
A. Measurements from the telescope discovered that the brightest object was actually two separate stars, halving their mass to around 100-150 solar masses each.
Q. What would have been the implications of a star with a mass of 200 to 300 solar masses existing in the galaxy?
A. It would have made it by far the most massive known star in the galaxy and put it considerably above the currently believed upper mass limit for individual stars.
Q. How much did NASA’s Hubble Space Telescope discover that Pismis 24-1 is actually two separate stars?
A. Their mass was halved to around 100-150 solar masses each.
Q. What is NGC 6357?
A. The larger emission nebula in which Pismis 24 lies.
Q. Who are the people credited for the image of Pismis 24?
A. NASA, ESA, and Jesús Maíz Apellániz (Instituto de Astrofísica de Andalucía, Spain).
Q. What is the current upper mass limit for individual stars in the galaxy?
A. About 150 solar masses.
Q. When was the image of Pismis 24 released?
A. December 11, 2006.
