 estimated 13.2 billion years old.
Astronomers usually cannot tell the age of an individual star. There are certain stars that we know are very young, and others that are very old, but for most stars we cannot tell. When we have a large group of stars, however, we can tell its age. The age of an individual star can vary; they were all made at different times and have different life spans. Stars can range from a few million to a several billion years old. The oldest star yet discovered, HE 1523-0901, is an estimated 13.2 Blue Giant Blue stars are large and compact, this causes them to burn their fuel quickly which in turn makes their temperature very hot. These stars often run out of fuel in only 10,000 - 100,000 years. A blue giant is extremely bright. Like a lighthouse, they shine across a great distance. All stars are in galaxies in a universe of unimaginable dimensions. Our planet orbits a sun that is one of billions of stars in the Milky Way, a galaxy in a group of galaxies that occupies only about onemillionth of the observable universe. All galaxies are moving away from one another. Blue Giant Stars Blue Giant Blue stars are large and compact, this causes them to burn their fuel quickly which in turn makes their temperature very hot. These stars often run out of fuel in only 10,000 - 100,000 years. A blue giant is extremely bright. Like a lighthouse, they shine across a great distance. To explain this problem further, consider an exploding star (supernova) at, say, an accurately measured 100,000 light-years away. Remember we are using this explanation in a 10,000-year-old universe. As the astronomer on Earth watches this exploding star, he is not just receiving a beam of light. Question: How can the light of stars billions of light years away from the earth have reached us if the earth is only thousands of years old?. Answer: Distant Starlight-A light-year is the maximum distance that light can travel in one year in the vacuum of space. It is also a great way to tell the age of a star. Scientists can look at the spectra of a star and tell its temperature, which is related to the size, etc. In turn, this information reveals how much hydrogen or helium is left inside the star. We know the rate at which stars burn the gases.
http://www.scientificamerican.com/article/how-do-scientists-determi/ http://www.answers.com/Q/How_old_are_stars http://www.kidsastronomy.com/stars/blue_giant_star.html http://astro.unl.edu/observatory/art3a.html http://www.kidsastronomy.com/stars/blue_giant_star.html http://christiananswers.net/q-aig/aig-c005.html http://www.gotquestions.org/star-light.html http://www.windows2universe.org/kids_space/starlife.html
how old are stars