The Merope Nebula

Pleiades_Spitzer_MeropeThe Merope Nebula (aka NGC 1435) is a diffuse reflection nebula in the Pleiades star cluster, surrounding the 4th magnitude star Merope. It appears to be about the size of the full moon. It is illuminated entirely by the star Merope which is embedded in the nebula. The nebula appears blue in visible light photographs because of the fine carbon dust spread throughout the cloud. The false color image above was put together using infrared data from the Spitzer Space Telescope. The visible light image below was taken by an amateur astronomer.

Image Credits: NASA / Karol Masztalerz (CC BY-SA 4.0)

The Pleiades

Pleiades_largeThe Pleiades, one of my favorite sights in the autumn and winter skies, clear the tree top by around 9 pm in November. Take a look at the real star cluster on a clear night. Click on the image to embiggen it.

Image Credit: NASA, ESA, AURA/Caltech, Palomar Observatory
The science team consists of: D. Soderblom and E. Nelan (STScI), F. Benedict and B. Arthur (U. Texas), and B. Jones (Lick Obs.)

Reflecting Merope

Starlight is slowly destroying this wandering cloud of gas and dust seen in the Pleiades star cluster. The star Merope is just out of the frame on the left of this picture taken by the Hubble Space Telescope. During the past 100,000 years, part of the cloud has moved so close to Merope that the star’s light is having a very dramatic effect. The pressure of the light is repelling the dust in the reflection nebula, and the smaller dust particles are repelled more quickly. As a result, the cloud has become stratified, seeming to point toward Merope. The closest particles are the most massive and the least affected by the radiation pressure. This nebula will eventually be blown apart by starlight.

Image Credit: NASA

Seven Sisters

Earlier this week, I blogged about looking at Venus passing in front of the Pleiades. If you missed it, there are nice pictures here and here. The sky is marvelous in visible light, but what we can see with the expanded range of infrared, ultraviolet, and x-ray instruments on orbit is astounding!

For example, M45, the lovely Pleiades or Seven Sisters star cluster, is well-known in astronomical images for its striking blue reflection nebulae. In visible wavelengths, the starlight is scattered and reflected by dust, but in this infrared image by the Spitzer Space Telescope, the dust itself glows. The false color image spans about 1 degree of sky (about seven light-years at the distance of the Pleiades). The densest regions of the dust cloud is shown in yellow and red hues. Data from Spitzer survey have revealed many cool, low mass stars, brown dwarfs or failed stars, and possible planetary debris disks.

Image Credit: NASA