Hubble Resolves Pismis 24-1
Left: ACS WFC image of emisison nebula NGC 6357 with the star Pismis 24-1 in the centre (the brightest star).
Middle: Looking closer at Pismis 24-1 with Hubble's ACS High Resolution Channel (HRC) it becomes clear that it is in reality two stars.
Right: ACS HRC image close-up showing the two stars comprising Pismis 24-1. Initially it was thought to be a single star with an incredibly large mass of 200 to 300 solar masses. New NASA/ESA Hubble measurements of the star, have, however, resolved Pismis 24-1 into two separate stars, of around 100 solar masses each.