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arXiv 0705.2941astro-ph
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在rho Oph主云和其它恒星形成区中星前核的尘埃温度：核质量函数的结果

The dust temperatures of the prestellar cores in the rho Oph main cloud and in other star forming regions: consequences for the core mass function

D. Stamatellos, A. P. Whitworth, D. Ward-Thompson

备注：
MNRAS accepted
发表信息：
Mon.Not.Roy.Astron.Soc.379:1390-1400,2007
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摘要：

考虑到该地区的3D几何形状，以及来自星际辐射场和附近发光的B2 V恒星HD 147879的外部加热，我们估计了rho Oph主云中团块的尘埃温度。我们发现，星前核的观测区（即在光学视亮度大于7等的情况下）的温度低于~10- 11 K。这些尘埃温度比以前对同一地区的研究所假设的要小。我们使用新的尘埃温度估计的质量的星前核心的rho Oph主云从毫米观测，我们发现核心质量大于以前的估计的一个因素~2-3。这影响了该区域的核心质量函数（CMF）;我们发现核心质量谱从斜率α ~1.5变陡到斜率α ~2.5的质量已经从~0.5 Msun移动到~ 1 Msun。与其他恒星形成区（如猎户座）的CMF相比，没有迹象表明它会在完整性极限（~0.2Msun）下翻转，但CMF可能会在~0.4Msun时变平。我们将我们的结果推广到金牛座和猎户座的星前核。在金牛座，加热星前核心的环境辐射场被认为比在ρ Oph弱。因此，金牛座核心的尘埃温度预计将低于10-11 K，猎户座的辐射场被认为是标准星际辐射场的10^3倍。基于这一假设，我们估计猎户座星前核心的尘埃温度约为20- 30 K。

英文摘要：

We estimate the dust temperatures of the clumps in the rho Oph main cloud taking into account the 3D geometry of the region, and external heating from the interstellar radiation field and from HD147879,a nearby luminous B2V star, which is believed to dominate the radiation field in the region. We find that the regions where prestellar cores are observed (i.e. at optical visual extinctions >7 mag) are colder than ~10-11K. These dust temperatures are smaller than those which previous studies of the same region have assumed. We use the new dust temperatures to estimate the masses of the prestellar cores in the rho Oph main cloud from mm observations, and we find core masses that are larger than previous estimates by a factor of ~2-3. This affects the core mass function (CMF) of the region; we find that the mass at which the core mass spectrum steepens from a slope alpha~1.5 to a slope alpha~2.5 has moved from ~0.5 Msun to ~1Msun. In contrast with the CMF in other star forming regions (e.g. Orion), there is no indication for a turnover down to the completeness limit (~0.2Msun), but the CMF may flatten at around ~0.4Msun. We generalize our results to the prestellar cores in Taurus and in Orion. In Taurus the ambient radiation field heating the prestellar cores is believed to be weaker than than that in rho Oph. Hence, the dust temperatures of the cores in Taurus are expected to be below ~ 10-11 K.In Orion the radiation field is believed to be 10^3 times stronger than the standard interstellar radiation field. Based on this assumption we estimate that the dust temperatures of the prestellar cores in Orion are around ~20-30K.

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