Credit: X-ray: NASA/CXC/IASF Palermo/M.Del Santo et al.
Watch Where You Wander
The word "planet" means "wanderer". From our vantage on earth, the planets of our solar system seem to wander back and forth through the field of stars. Perhaps planets in other star fields wander too. In fact, astronomers may have seen a planet in a star cluster called NGC 6388 wander too close to a compact, burnt-out remnant core of a dead star, and get ripped apart by the dead star's intense gravity. At least that's one explanation for the strange burst of energy seen arising from this particular star cluster. The first clue was an outpouring of energetic X-ray radiation detected by the INTEGRAL satellite. Astronomers at first thought this outburst was produced by a black hole believed to be lurking in the center of the cluster. However subsequent observations by the Chandra X-ray Observatory showed that the transient X-ray source was not located near the center of the cluster, but instead off to one side. The Chandra X-ray image of NGC 6388 is shown above. Subsequent monitoring with the Swift X-ray Telescope showed a decline in emission that some astronomers believe is characteristic of the accretion of a planet onto the surface of a white dwarf star. If a normal star in NGC 6388 was orbited by a planet, an encounter with another star may have pushed the planet from its orbit and sent it on a trajectory where it could have encountered a white dwarf. The white dwarf's intense gravity would then have been powerful enough to pull the planet apart, and material from the planet raining down on the surface of the white dwarf could have generated the bright, energetic X-ray emission.
Published: April 27, 2015
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Page Author: Dr. Michael F. Corcoran
Last modified Monday, 11-May-2015 08:04:01 EDT