Benvenuti in queste pagine dedicate a scienza ed arte. Amelia Carolina Sparavigna

Tuesday, January 4, 2011

Chandra Proxima Centauri

"The Chandra X-ray Observatory is a satellite launched on STS-93 by NASA on July 23, 1999. It was named in honor of Indian-American physicist Subrahmanyan Chandrasekhar who is known for determining the maximum mass for white dwarfs. "Chandra" also means "moon" or "luminous" in Sanskrit. Chandra Observatory is the third of NASA's four Great Observatories. The first wasHubble Space Telescope; second the Compton Gamma Ray Observatory, launched in 1991; and last is the Spitzer Space Telescope." read more at
See at http://chandra.harvard.edu/photo/2004/proxima/ images of Proxima Centauri.
"Proxima Centauri: A red dwarf star 4 light years from the Sun. (Credit: NASA/CXC/SAO). X-ray observations of Proxima Centauri, the nearest star to the Sun, have shown that its surface is in a state of turmoil. Flares, or explosive outbursts occur almost continually. This behavior can be traced to Proxima Centauri's low mass, about a tenth that of the Sun. In the cores of low mass stars, nuclear fusion reactions that convert hydrogen to helium proceed very slowly, and create a turbulent, convective motion throughout their interiors. This motion stores up magnetic energy which is often released explosively in the star's upper atmosphere where it produces flares in X-rays and other forms of light. X-rays from Proxima Centauri are consistent with a point-like source. The extended X-ray glow is an instrumental effect. The nature of the two dots above the image is unknown - they could be background sources."