Messier 45 is more commonly referred to as the Pleiades, and is
the most famous open star cluster among amateur astronomers and
the general public alike. Easily visible to the naked eye during
the northern Winter, this cluster has been featured in
literature over three millennia! Research compilations now
suggest that about 500 stars, mostly faint, are gravitationally
bound together as the Pleiades. Visible: DSS, Visible: Color - ©
AAO, Royal Observatory, Edinburgh Let us begin our examination
of Messier 45 with a look at the visible light images (above).
The black-and-white and color images both reveal wispy veils of
fog surrounding the brightest stars. These reflection nebulae
are produced by dust particles within the cluster. The chemical
composition of the reflected light (as determined through
spectroscopy) is identical to that of the blue stars, thereby
confirming that the nebulae are simply stellar light reflected
to our line of sight by the dust. The blue tint is a consequence
of the fact that the ill