Gamma Crucis, or Gacrux, is the third-brightest star in the constellation of Crux The Cross ("The Southern Cross") and forms the head of the cross. It is the 31st star in the Nautical Almanac.
Gacrux is a red giant star well off the Main Sequence, and the closest red giant to Earth, being only 88 light years (528,000,000,000,000 miles) away.
Gacrux is a second magnitude star. It is one and a half times as massive as our Sun, but 84 times the size. It is 820 times as luminous as the Sun, but burns at a relatively low temperature of 6,000 F. Gacrux is 20 million years old. It is burning barium, a heavy metal, either a sign of advancing age or possibly due to having absorbed an orbital companion during its expansion into a red giant.
Gacrux was known to the ancients (due to precession it was visible in the northern hemisphere thousands of years ago), and was known as "The Ruby" due to its color. Gacrux's prominent appearance and position in the Southern Cross was a religious aid to South Seas missionaries, who claimed the star was a symbol of Christ's head on the cross.
No comments:
Post a Comment