Etoiles dans l'amas globulaire Omega du Centaure - Omega Centauri seen by Hubble space telescope...

Etoiles dans l'amas globulaire Omega du Centaure - Omega Centauri seen by Hubble space telescope - Situe a 16 000 annees - lumiere de la Terre dans la constellation australe du Centaure, Omega du Centaure contient plusieurs millions d'etoiles et est un des objets les plus ages de notre galaxie. Cette image obtenue par le telescope spatial Hubble en juillet 2009 ne montre qu'une petite partie de cet amas, ou 100 000 etoiles sont visibles. Hubble Space Telescope snapped this panoramic view of a colorful assortment of 100,000 stars residing in the crowded core of a giant star cluster. The image reveals a small region inside the massive globular cluster Omega Centauri, which boasts nearly 10 million stars. The stars in Omega Centauri are between 10 billion and 12 billion years old. The cluster lies about 16,000 light - years from Earth. This is one of the first images taken by the new Wide Field Camera 3 (WFC3), installed aboard Hubble in May 2009, during Servicing Mission 4. The majority of the stars in the image are yellow - white, like our Sun. These are adult stars that are shining by hydrogen fusion. Toward the end of their normal lives, the stars become cooler and larger. These late - life stars are the orange dots in the image. Even later in their life cycles, the stars continue to cool down and expand in size, becoming red giants. These bright red stars swell to many times larger than our Sun's size and begin to shed their gaseous envelopes. After ejecting most of their mass and exhausting much of their hydrogen fuel, the stars appear brilliant blue. Only a thin layer of material covers their super - hot cores. These stars are desperately trying to extend their lives by fusing helium in their cores. At this stage, they emit much of their light at ultraviolet wavelengths. When the helium runs out, the stars reach the end of their lives. Only their burned - out cores remain, and they are called white dwarfs (the faint blue dots in the image). White dwarfs are no