天文学家近日宣布他们在银河系里发现一颗由曾经的庞大恒星转变而成的体积较小的行星，这颗行星完全由
钻石构成。
天文学家近日在银河系中发现了一颗“
钻石”行星，即整颗行星晶莹剔透，闪闪发亮，最为特别的是，它的岩石块都是由类似
钻石的珍贵物质所组成。这是科学家在宇宙中发现的首颗
钻石行星。
据悉，国际研究小组首先在银河系中发现了一颗名为“ J1719-1438”的非凡脉冲星，在这颗脉冲星的旁边发现了一颗围绕它旋转的闪亮行星，即“
钻石”行星。脉冲星是小型星球，会向外发出无线电波光束。
“
钻石”行星围绕脉冲星一圈的时间约为两小时十分钟。研究小组认为这颗“
钻石行星”是一颗原始恒星的剩余物，它的大部分物质都被脉冲星吸走了。除碳之外，星球上氧的含量较多，越往碳密度高的中心氧含量越低。而“
钻石行星”的高密度意味着像氢气、氦气这种较轻的气体在该星球上不存在。
原文：Astronomers have spotted an exotic planet that seems to be made of diamond racing around a tiny star in our galactic backyard.
The new planet is far denser than any other known so far and consists largely of carbon. Because it is so dense, scientists calculate the carbon must be crystalline, so a large part of this strange world will effectively be diamond.
"The evolutionary history and amazing density of the planet all suggest it is comprised of carbon -- i.e. a massive diamond orbiting a neutron star every two hours in an orbit so tight it would fit inside our own Sun," said Matthew Bailes of Swinburne University of Technology in Melbourne.
Lying 4,000 light years away, or around an eighth of the way toward the center of the Milky Way from the Earth, the planet is probably the remnant of a once-massive star that has lost its outer layers to the so-called pulsar star it orbits.
Pulsars are tiny, dead neutron stars that are only around 20 kilometers (12.4 miles) in diameter and spin hundreds of times a second, emitting beams of radiation.
In the case of pulsar J1719-1438, the beams regularly sweep the Earth and have been monitored by telescopes in Australia, Britain and Hawaii, allowing astronomers to detect modulations due to the gravitational pull of its unseen companion planet.
The measurements suggest the planet, which orbits its star every two hours and 10 minutes, has slightly more mass than Jupiter but is 20 times as dense, Bailes and colleagues reported in the journal Science on Thursday.
In addition to carbon, the new planet is also likely to contain oxygen, which may be more prevalent at the surface and is probably increasingly rare toward the carbon-rich center.
Its high density suggests the lighter elements of hydrogen and helium, which are the main constituents of gas giants like Jupiter, are not present.
Just what this weird diamond world is actually like close up, however, is a mystery.
"In terms of what it would look like, I don't know I could even speculate," said Ben Stappers of the University of Manchester. "I don't imagine that a picture of a very shiny object is what we're looking at here."(来源：reuters）
Moongirl 最后编辑于 2011-10-21 17:22:23
