The Stellar Initial Mass Function in 2007: A Year for Discovering Variations
The Stellar Initial Mass Function in 2007: A Year for Discovering Variations
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2007年恒星初始质量函数：发现变异的一年
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
B. Elmegreen
中科院分区：
文献类型：
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作者：
B. Elmegreen
回顾了宇宙学时代形成的星系团、场区、星系和区域的IMF特征质量Mc和斜率Gamma。局部恒星的形成具有一定的均匀的Mc和Gamma。总结了伽玛的统计变化，以及这些变化施加的限制。宇宙恒星的形成在中高质量恒星时似乎既有较高的Mc，又有较浅的斜率。银河系的中心可能也有一个浅坡度。场区的坡度比星系团略微陡峭，但这可能是低质量恒星脱离星系团和星团的增强漂移的结果。矮星系也有更陡峭的坡度。文中还对前星团的观测结果进行了回顾。恒星前的星团似乎与恒星具有大致相同的质量功能，因此被认为是恒星的主要前身。如果是这样的话，IMF通常是由气相过程决定的。褐矮星的形成也有许多恒星形成的特征，这表明它们是由类似的机制形成的。
The characteristic mass M_c and slope Gamma of the IMF are reviewed for clusters, field regions, galaxies, and regions formed during cosmological times. Local star formation has a somewhat uniform M_c and Gamma. Statistical variations in Gamma are summarized, as are the limitations imposed by these variations. Cosmological star formation appears to have both a higher M_c and a slightly shallower slope at intermediate to high stellar mass. The center of the Milky Way may have a shallow slope too. Field regions have slightly steeper slopes than clusters, but this could be the result of enhanced drift of low mass stars out of clusters and associations. Dwarf galaxies also have steeper slopes. Results from the observation of pre-stellar clumps are reviewed too. Pre-stellar clumps appear to have about the same mass function as stars and are therefore thought to be the main precursors to stars. If this is the case, then the IMF is generally determined by gas-phase processes. Brown dwarf formation also shares many characteristics of star formation, suggesting that they form by similar mechanisms.