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Messier Designation : M45
Melotte Classification : None

Position :  
Right Ascension = 3 (hours) : 47 (minutes) 
Declination = +24 degrees : 07 min

Constellation : Taurus   

Narrative : 
The estimated age of the cluster is around 100 million years.   The life expectancy of this cluster is an additional 250 million years. 

This cluster is also known as the "Seven Sisters" who, in greek mythology, were the daughters of Atlas & Pleione and were name: Alcyone, Asterope (a double star), Electra, Maia, Merope, Taygeta and Celaeno. In Japan this cluster is known as "Subaru"

The blue color of the cluster is the result of a reflection nebulae (gas and dust cloud) with glows from the light of the stars in the cluster.  Thought to be left over matter from the formation of the stars in the cluster the cluster and the nebulae have different radial velocities suggesting that the nebulae is unrelated to the cluster and is just crossing the cluster.

The first recorded mention of this star cluster was by Hesiod between 1000 and 700  B.C.  

The cluster contains about 500 stars spread over 2 degrees of arc field (or about 4 times the diameter of the moon) with about 100 stars being concentrated toward the center. 

Unusual characteristics of the cluster are: the presence of stars with rapid rotations of 150 / 300 km/sec at there surfaces which become slightly flattened in shape rather than spherical, the existence of white dwarfs which are intriguing due to the relatively young age of the cluster and the fact that white dwarfs are very old stars on the last legs of their life cycles and the existence of rare brown dwarf stars.