Young Neighbors
The signature star pattern of summer -- the Summer Triangle -- is quite low in the east at nightfall. Its brightest member is Vega; Deneb is to its lower left, with Altair farther to its lower right.
Vega and Altair are among our closest neighbors. Vega's about 25 light-years away, and Altair is even closer.
Both stars are also younger than our own star, the Sun. In fact, a recent study by astronomers at McDonald Observatory suggests that the Sun is among the oldest stars in our region of the galaxy.
A team led by Carlos Allende Prieto studied 118 bright, Sun-like stars that are within about 50 light-years. The team used telescopes at McDonald and in Chile to measure the chemical compositions of the stars. It was the most detailed study of the bright stars in our neighborhood to date.
The survey found that most of the stars have higher percentages of heavy elements than the Sun does -- elements like oxygen, carbon, and silicon.
These elements are created inside stars. When the stars die, they cast much of their material into space, where it can form new stars. As a result, each new generation of stars has higher levels of these elements.
The fact that the Sun contains less of these elements probably means that it's older than most of the similar stars around us.
The astronomers are extending their study to stars within several hundred light-years. That'll provide a better look at how the Sun compares to its neighbors.
Script by Damond Benningfield, Copyright 2006
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