Editing Pleiades (section)

== Reflection nebulosity ==
[[File:Reflection nebula IC 349 near Merope.jpg|thumb|upright=1.0|[[Hubble Space Telescope]] image of reflection nebulosity near [[Merope (star)|Merope]] ([[IC 349]])]]

With larger amateur telescopes, the nebulosity around some of the stars may be easily seen, especially when long-exposure photographs are taken. Under ideal observing conditions, some hint of nebulosity around the cluster may be seen even with small telescopes or average binoculars. It is a [[reflection nebula]], caused by dust reflecting the blue light of the hot, young stars.

It was formerly thought that the dust was left over from the [[star formation|formation]] of the cluster, but at the age of approximately 100 million years generally accepted for the cluster, almost all the dust originally present would have been dispersed by [[radiation pressure]]. Instead, it seems that the cluster is simply passing through a particularly dusty region of the [[interstellar medium]].<ref name="Gibson2003" />

Studies show that the dust responsible for the nebulosity is not uniformly distributed, but is concentrated mainly in two layers along the line of sight to the cluster. These layers may have been formed by deceleration due to [[radiation]] pressure as the dust has moved toward the stars.<ref>
{{cite journal
 |author=Gibson, Steven J.
 |author2=Nordsieck, Kenneth H.
 |date=2003
 |title=The Pleiades Reflection Nebula. II. Simple Model Constraints on Dust Properties and Scattering Geometry
 |journal=[[Astrophysical Journal]]
 |volume=589 |issue=1
 |pages=362–377
 |bibcode=2003ApJ...589..362G
 |doi=10.1086/374590
|doi-access=free
 }}</ref>