The left side of this collage shows the central part of the young star cluster R136 as it can be seen in the ultraviolet. Due to the high-resolution of Hubble in the ultraviolet the individual stars in this dense cluster can be resolved and studied. The right side shows a pseudo-image, created from the UV spectra collected with the Space Telescope Imaging Spectrograph (STIS). These spectra have been used by scientists to determine the properties of the stars in R136. The boundary of the 17 slit locations is outlined in white in the left image. The long-slit data from the spectrograph have been compressed to the width of the slits and stacked to create a pseudo-image. This allows the slit locations to be matched to stars in the left image.

The star cluster R136 at the heart of the Tarantula nebula was known to harbor 4 very massive stars. New data taken with the STIS spectrograph on board Hubble reveals a total of 9 monsters stars that appear to have masses around or well in excess of a hundred solar masses.

This is the first paper in a series discussing the UV spectra of the brightest objects.  The “monster stars” fully dominate the strong helium emission lines that have also been seen in other very young massive star clusters, indicating that such extreme stars are more common than we thought. This argues in favor of extending the initial mass function well beyond the canonical limit of 100 solar masses.



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