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Astronomy in Orbit
POSTED 5 MAY 2005

Enchanting Chandra
X-rays are messengers from exotic corners of the universe, where particles collide at almost the speed of light, or where temperatures are measured in millions of degrees. artist's rendering of winged, tubular, silver and grey spacecraftBut X-rays go right through the garden-variety mirror, so you need a special gizmo to collect and study them. You need the Chandra X-ray Observatory, a high-tech 45-foot pipe that collects X-rays by glancing them off a cylindrical mirror.

Chandra graphic from NASA's Goddard Space Flight Center

Because X-rays are produced by hot, energetic stuff, Chandra specializes in looking at things that go zoom in the night: Black holes, active galactic nuclei, collisions between galaxies, and other action-movie astronomical anomalies.

Detailed diagram of X-ray telescope orbiting Earth
Launched in 1999, the X-ray telescope Chandra makes sharp pix of hot stuff. The scope orbits one-third of the distance to the moon. Diagram: Chandra

Star eat star
It's a celestial fairy tale straight from the brothers Grimm: A white dwarf sucks the life blood from a red giant. In space, Chandra has watched stellar winds blow gas from the outside of the red giant. top: A red giant star is sucked into a white dwarf, bottom:When the gas gets caught by the white dwarf's gravity, a gas bridge forms between the stars. The blue zone is an accretion disk where high-speed particle collisions make X-rays visible to Chandra.

TOP: Age before beauty, or mass before size: Mira A, a red giant, is being sucked dry by Mira B, a white dwarf. Photo: NASA/CXC/SAO/M. Karovska et al

BOTTOM: With the help of an ultraviolet image of Mira A and B from Hubble, scientists identified this X-ray outburst from the red giant Mira A (right). Photo: NASA/M. Karovska et al.

Mira A and B are 420 light years from Earth; the distance between the stars is about twice Pluto's distance from the Sun. The red giant has become huge and unstable, with a diameter about 600 times that of our Sun. Energetic nuclear reactions are making it pulsate. Once it burns up its nuclear fuel, it will collapse into a white dwarf. Mira B already is a white dwarf: It's as big as Earth, but half-a-million times more massive.

See the Chandra slide show.

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