CARMA-NRO Orion Survey: Unbiased Survey of Dense Cores and Core Mass Functions in Orion A
CARMA-NRO Orion Survey: Unbiased Survey of Dense Cores and Core Mass Functions in Orion A
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DOI：
10.3847/1538-4365/aca4d4
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发表时间：
2022-11
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通讯作者：
H. Takemura;F. Nakamura;H. Arce;N. Schneider;V. Ossenkopf-Okada;Shuo Kong;S. Ishii;K. Dobashi;T. Shimoikura;P. Sanhueza;T. Tsukagoshi;P. Padoan;R. Klessen;P. Goldsmith;B. Burkhart;D. Lis;Á. Sánchez-Monge;Y. Shimajiri;R. Kawabe
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作者：
H. Takemura;F. Nakamura;H. Arce;N. Schneider;V. Ossenkopf-Okada;Shuo Kong;S. Ishii;K. Dobashi;T. Shimoikura;P. Sanhueza;T. Tsukagoshi;P. Padoan;R. Klessen;P. Goldsmith;B. Burkhart;D. Lis;Á. Sánchez-Monge;Y. Shimajiri;R. Kawabe
致密核心的质量分布是理解星星形成过程的潜在关键。应用聚类分析的CARMA-NRO猎户座C18 O（J = 1-0）的数据，我们确定了2342致密的核心，其中约22%的维里比小于2，可以归类为重力束缚的核心。导出的核心质量函数（CMF）对于与原恒星无关的无恒星核心，其斜率与萨尔彼得的初始质量函数（IMF）相似，质量范围在1 M <$以上，峰值在0.1 M <$。我们根据decl将云划分为四个部分，OMC-1/2/3、OMC-4/5、L1641 N/V380 Ori和L1641 C，并推导出这些区域中的CMF。我们发现，质量大于10 M <$的无星核只存在于OMC-1/2/3中，而OMC-4/5、L1641 N和L1641 C中的CMF在5-10 M <$附近被截断。根据每个分区域中束缚无星核和第二类天体的数量比例，束缚无星核的寿命估计为5-30次自由落体，与以前对其他区域的研究一致。此外，我们讨论了核心增长的质量吸积从周围的云材料来解释的一致性峰值质量之间的IMFs和CMFs。在一个核心寿命内核心质量加倍所需的质量吸积率比邦迪-霍伊尔吸积率大2倍。这意味着，更多的动态吸积过程需要增长的核心。
The mass distribution of dense cores is a potential key to understanding the process of star formation. Applying dendrogram analysis to the CARMA-NRO Orion C18O (J = 1–0) data, we identify 2342 dense cores, about 22% of which have virial ratios smaller than 2 and can be classified as gravitationally bound cores. The derived core mass function (CMF) for bound starless cores that are not associate with protostars has a slope similar to Salpeter’s initial mass function (IMF) for the mass range above 1 M ⊙, with a peak at ∼0.1 M ⊙. We divide the cloud into four parts based on decl., OMC-1/2/3, OMC-4/5, L1641N/V380 Ori, and L1641C, and derive the CMFs in these regions. We find that starless cores with masses greater than 10 M ⊙ exist only in OMC-1/2/3, whereas the CMFs in OMC-4/5, L1641N, and L1641C are truncated at around 5–10 M ⊙. From the number ratio of bound starless cores and Class II objects in each subregion, the lifetime of bound starless cores is estimated to be 5–30 freefall times, consistent with previous studies for other regions. In addition, we discuss core growth by mass accretion from the surrounding cloud material to explain the coincidence of peak masses between IMFs and CMFs. The mass accretion rate required for doubling the core mass within a core lifetime is larger than that of Bondi–Hoyle accretion by a factor of order 2. This implies that more dynamical accretion processes are required to grow cores.