疏散星團
Massive Stars in Open Cluster Pismis 24 <br />
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<img src="http://i15.tinypic.com/2j10x8w.jpg" border="0" onclick="zoom(this)" onload="attachimg(this, 'load')" alt="" /><br />
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影像版權: NASA, ESA and J. M. Apellniz (IAA, Spain).<br />
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<font color="navy">Explanation:</font><br />
How massive can a normal star be? Estimates made from distance, brightness and standard solar models had given one star in the open cluster Pismis 24 over 200 times the mass of our Sun, making it a record holder. This star is the brightest object located just to the right of the gas front in the above image. Close inspection of images taken recently with the Hubble Space Telescope, however, have shown that Pismis 24-1 derives its brilliant luminosity not from a single star but from three at least. Component stars would still remain near 100 solar masses, making them among the more massive stars currently on record. Toward the image left, stars are still forming in the associated emission nebula NGC 6357, including several that appear to be breaking out and illuminating a spectacular cocoon. <br />
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<font color="navy">說明:</font><br />
恆星能有多重？這顆位於疏散星團 Pismis 24 的恆星，可以藉由距離，亮度以及標準太陽模型來估計它的質量約為太陽質量的200倍，是目前已知最重的恆星。在上圖中，它就是位於氣體右邊最亮的那顆星星。然而，哈伯太空望遠鏡最近拍攝了一幅更高解析度的影像，發現 Pismis 24-1的亮度並不是單獨一顆恆星貢獻的，它至少是由<br />
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<font size="2">資料來源: Scientific American<br />
Department of Physics, NCKU</font>