Fig7_16 Pleiades Open Star Cluster

Fig7_16 Pleiades Open Star Cluster

Fig. 7.16 . These luminous blue-colored stars are members of the open star cluster known as the Pleiades or Seven Sisters, as well as M 45. It can be seen with the unaided eye, without binoculars or a telescope. The Pleiades contains about 3,000 stars, is only 440 light-years away, and about 13 light-years across. Interstellar dust reflects the blue light of the hot stars, creating the hazy nebulous appearance. The telescope causes the prominent, cross-shaped diffraction spikes. Astronomers estimate that the young Pleiades stars were formed just 100 million years ago, and that the cluster will survive for another 250 million years before dispersing. This color-composite image was taken in 1986 with a 48-inch Schmidt telescope as part of the second Palomar Observatory Sky Survey. (Courtesy of NASA/ESA/AURA/Caltech.)

Copyright 2010, Professor Kenneth R. Lang, Tufts University