Clusters Red supergiant star

rsgc1, first of several massive clusters found contain multiple red supergiants.

red supergiants no more 25 million years old , such massive stars expected form in relatively large clusters of stars, expected found near prominent clusters. short-lived compared other phases in life of star , form relatively uncommon massive stars, there small numbers of red supergiants in each cluster @ 1 time. example, in substantial double clusters in perseus there single red supergiant, s persei, while massive hodge 301 cluster in tarantula nebula contains three. until 21st century largest number of red supergiants known in single cluster 5 in ngc 7419. red supergiants found singly, example betelgeuse in orion ob1 association , antares in scorpius-centaurus association.

since 2006, series of massive clusters have been identified bear base of crux-scutum arm of galaxy, each containing multiple red supergiants. rsgc1 contains @ least 12 red supergiants, rsgc2 (also known stephenson 2) contains @ least 26, rsgc3 contains @ least 8, , rsgc4 (also known alicante 8) contains @ least 8. total of 80 confirmed red supergiants have been identified within small area of sky in direction of these clusters. these 4 clusters appear part of massive burst of star formation 10-20 million years ago @ near end of bar @ centre of galaxy. similar massive clusters have been found near far end of galactic bar, not such large numbers of red supergiants.