The Cat's Eye Nebula(NGC 6543) is one of the best known planetarynebulae in the sky.Its haunting symmetries are seen in the very central regionof this stunning false-color picture, processed to reveal theenormous but extremely faint halo of gaseous material, over threelight-years across, which surrounds the brighter, familiar planetary nebula.Made with data from th Nordic Optical Telescopein the Canary Islands, the composite pictureshows emission fromnitrogen atoms as red and oxygen atoms as green and blue shades Planetarynebulae have long been appreciated as a final phas in the life of a sun-like star.Only much more recently however, have some planetaries bee found to have haloslike this one, likely formed of material shrugged off duringearlier active episodes in the star's evolution.While the planetarynebula phase is thought to last for around 10,000 years,astronomers estimate the age of the outer filamentary portionsof this halo to be 50,000 to 90,000 years.
0 comments:
Post a Comment