The Pleiades (M45)
Magnitude - 1.2
Type - Bright open cluster associated with a reflection nebulae,
Constellation - Taurus,
Distance - 410 light years,
Size - The dipper shaped asterism comprised of the cluster's brightest
members is about
7 light years across. The entire open cluster spans as much as 20 light
years.
This bright open cluster is perhaps
one of the best known objects in the skies. Under ideal visual observing
conditions nine stars can be seen in the dipper shaped asterism at the center
of the cluster. However, there are nearly 300 (mostly faint) confirmed
Pleiades members. The blue color is star light reflecting from a dust
cloud that the cluster just happens to be moving through. Burnham's
Celestial Handbook reports that the Pleiades group is one of the nearest
open or "galactic" star clusters. The nine brightest members are
concentrated in a region approximately 7 light years in diameter. All of
the brightest members are "B" type stars. Eta Tauri, also known
as Alcyone, is the brightest member of the cluster and is nearly 1000 times more
luminous than the Sun. It is also estimated to be 10 times more massive
than the Sun. This star cluster has had a prominent role in the mythology
of many cultures. An interesting treatment of this history and mythology
can be found in Burnham's Celestial Handbook.
