Generation Gap Clusters |
|
|
Many, if not most, stars in our Galaxy are members of a multiple star
system. Extreme examples are star clusters: gravitationaly bound groupings
of dozens to thousands of individual stars, all formed at the same time.
Here we show to examples of star clusters: on the left is M34, in the constellation of Perseus, and on the right is M67, in Cancer. Both are examples of "open" clusters, which are found in the disk of our Galaxy. Examine these two clusters closely, and you will see that M34 has many bright blue stars, while the brightest stars in M67 are more red in color. This is because M34 is a much younger cluster. The bright blue stars are more massive than our Sun, and have formed within the last 100 million years or so. So what happened to these stars in M67, which is about 3 billion years old? The massive stars live relatively short lives, so that by the time M34 reaches the age fo M67, most will have died (as supernovae or planetary nebulae - see May); some will have become red giant stars, shining brightly like the red stars in M67. | |