太陽系最終的命運：白矮星周圍有行星（圖）

06-13

Planets Orbit Dead Stars

by Govert Shilling 胡德良譯

LONG BEACH. CALIFORNIA—Planets appear to be everywhere astronomers look, even in orbit around white dwarf stars—the compacted and slowly cooling "corpses" of stars like our own sun. At the 221st meeting of the American Astronomical Society here, researchers reported the discovery of a planetary system around a white dwarf in the famous Hyades star cluster. This cluster is only 150 light-years from Earth and easily visible to the naked eye on a bright winter night. It"s only the second time planets have been found in a cluster similar to the one that probably gave birth to our own sun. It"s circumstantial evidence, though: The planets apparently stir up the rocky asteroid belt of the system, and as a result, the white dwarf"s outer layers become "polluted" with asteroid dust, which in turn is detectable with sensitive spectroscopes. This may be the ultimate fate of our own solar system, after the sun sheds its gaseous mantle into space and condenses into a white dwarf.

加州長灘消息：天文學家們觀察到的地方到處是行星，甚至在白矮星周圍都有行星。白矮星是類似我們太陽的恆星在塌縮後慢慢冷卻的「死屍」。美國天文學會在這裡舉行的第221屆會議上，研究人員報道：他們發現在著名的畢星團周圍存在一個行星系統。畢星團距離地球僅僅150光年，在冬季晴朗的夜晚，人們用肉眼能夠很容易地看到。行星在類似於誕生太陽的星團中被發現，這僅僅是第二次。然而，有充分的證據表明，這些行星顯然攪亂了系統中的岩石小行星帶，結果這顆白矮星的外層受到了小行星塵的「污染」，而小行星塵可以被敏感的分光鏡探測到。這有可能就是我們太陽系的最終命運，到那時太陽的氣體外圍會流入太空，並凝縮成白矮星。