Rancho Las Voces: Nebulous Winds
(6) El retorno de Francis Ford Coppola

jueves, mayo 18, 2006

Nebulous Winds

SPACE.com Staff

D espite their beauty, these stellar winds herald the impending deaths of their parent stars.

Four different planetary nebulas – each with their own unique take on stellar death – appear in this collection observed by the Chandra X-ray Observatory and the Hubble Space Telescope.

Stars like our own Sun can generate a planetary nebula late in their life cycle after several billion years of activity. During that process a normal star expands into a red giant, spewing much of its mass outward at about 50,000 miles per hour and creating a relatively spherical cloud – the nebula – that shrouds its central core. Intense radiation at the core can then heat up the surrounding gas, jumpstarting it up to 1 million miles per hour, Chandra Observatory researchers said.

At 4.5 billion years old, the Sun won’t hit the red giant stage of its life cycle for another five billion years. Chandra and Hubble space telescope observations of the Ant Nebula (also known as Mz 3), BD+30-3639, Hen 3-1475 and NGC 7027 give astronomers a picturesque view of planetary nebulas at work. Chandra’s X-ray data appears in blue, while Hubble’s optical imagery fills in the greens and reds.

While most of these examples carry oddly eye-catching shapes, BD+30-3639 carries a spherical look. But appearances can be deceiving, and additional data suggests the view shown of the nebula looks on its pole.

Shock waves from the collision of high-speed gas with surrounding material are a likely cause of the hot bubbles observed by Chandra, but astronomers are still unclear of the origin of the funnel-like winds. One theory suggests they may be related to the strong magnetic field near a nebula’s hot stellar core, Chandra officials said.

Credit: Credit: X-ray: NASA/CXC/RIT/J.Kastner et al.; Optical/IR: BD +30 & Hen 3: NASA/STScI/Univ. MD/J.P.Harrington; NGC 7027: NASA/STScI/Caltech/J.Westphal & W.Latter; Mz 3: NASA/STScI/Univ. Washington/B.Balick.