兩項(xiàng)新的研究對某些恒星的不尋常的大小和組成提出了見解。 在這些氣態(tài)發(fā)光球體形成之前,，宇宙中只有氫,、氦和鋰元素。
最早出現(xiàn)的恒星通過發(fā)出最早的光線及產(chǎn)生最早的金屬而根本性地轉(zhuǎn)變了早期的宇宙,。
Michele Fumagalli及其同事現(xiàn)在根據(jù)在夏威夷的凱克望遠(yuǎn)鏡所做的觀測發(fā)現(xiàn)了2顆沒有可辨識出的金屬的恒星,。 這兩顆恒星是在宇宙大爆炸后約2百萬年時(shí)形成的。
在宇宙大爆炸時(shí)期產(chǎn)生了大量的恒星和星系,，天文學(xué)家預(yù)計(jì)這些恒星和星系中的大多數(shù)富含金屬,。
然而，該研究小組的結(jié)果意味著恒星和星系間的金屬的運(yùn)輸并沒有像以前所認(rèn)為的那樣有效率或普遍,。
過去的研究還提示,，最早的恒星要比太陽大數(shù)百倍。
然而,，Takashi Hosokawa及其同事在另外一則研究中所做的數(shù)值模擬揭示,，早期的恒星可能要小得多,。
他們的計(jì)算顯示了最早的恒星要成長至太陽的幾十倍之大的困難,。 這兩項(xiàng)研究的結(jié)果給早期恒星的形成所描繪的畫面略有不同,，這提示，恒星仍然還有值得探索的秘密,。(生物谷 Bioon.com)
doi:10.1126/science.1213581
PMC:
PMID:
Detection of Pristine Gas Two Billion Years After the Big Bang
Michele Fumagalli, John M. O'Meara, J. Xavier Prochaska
In the current cosmological model, only the three lightest elements were created in the first few minutes after the Big Bang; all other elements were produced later in stars. To date, however, heavy elements have been observed in all astrophysical environments. We report the detection of two gas clouds with no discernible elements heavier than hydrogen. These systems exhibit the lowest heavy-element abundance in the early universe and thus are potential fuel for the most metal poor halo stars. The detection of deuterium in one system at the level predicted by primordial nucleosynthesis provides a direct confirmation of the standard cosmological model. The composition of these clouds further implies that the transport of heavy elements from galaxies to their surroundings is highly inhomogeneous.
