Astronomy Picture of the Day
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2012 November 18
NGC 6357's Cathedral to Massive Stars
Image Credit:
NASA,
ESA and
J. M. Apellániz (IAA, Spain)
Explanation:
How massive can a normal star be?
Estimates made from distance, brightness and standard
solar models had given one star in the
open cluster Pismis 24
over 200 times the mass of our Sun, nearly making it the record holder.
This star is the brightest object located just above the gas front in the
above image.
Close inspection of images taken with the
Hubble Space Telescope,
however, have shown that Pismis 24-1 derives its
brilliant luminosity
not from a single star but from
three at least.
Component stars would still remain near 100 solar masses,
making them among the more
massive stars currently on record.
Toward the bottom of the image, stars are still forming in the associated
emission nebula
NGC 6357.
Appearing perhaps like a
Gothic cathedral, energetic stars near the center
appear to be breaking out and illuminating a
spectacular cocoon.
