Reflecting Merope

In the well known Pleiades star cluster, starlight is slowly destroying
this wandering cloud of gas and dust. The star Merope lies just off the
upper left edge of this picture from the Hubble Space Telescope. In the
past 100,000 years, part of the cloud has by chance moved so close to this
star - only 3,500 times the Earth-Sun distance - that the starlight itself
is having a very dramatic effect. Pressure of the star's light significantly
repels the dust in the reflection nebula, and smaller dust particles are
repelled more strongly. As a result, parts of the dust cloud have become
stratified, pointing toward Merope. The closest particles are the most massive
and the least affected by the radiation pressure. A longer-term result will
be the general destruction of the dust by the energetic starlight.