Star formation in the lambda orionis region. I. The distribution of young objects
Star formation in the lambda orionis region. I. The distribution of young objects
复制标题
猎户座 lambda 区域的恒星形成。
DOI：
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发表时间：
1982
期刊：
影响因子：
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通讯作者：
C. Lada
中科院分区：
文献类型：
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作者：
R. Duerr;C. Imhoff;C. Lada
我们对H.阿尔法帽。在一个面积约为100平方度（约5000 pc/sup 2/）的区域内的发射物体，以λ Orionis OB协会为中心。我们发现了83个物体，其中62个是以前在较早的，不太广泛的调查中发现的。大多数H…阿尔法帽。在该区域中的发射物体没有被投射到暗云材料上，许多看起来在扩展的中心区域内（即，约6/sup 0/ in直径）的低密度H II区。绝大多数的H…阿尔法帽。发射物体形成2/sup 0/ x 8/sup 0/ in范围的细长棒状结构。这些维度类似于产生OB和T协会的巨型分子云复合体。我们认为，H的空间分布。阿尔法帽。发射对象和OB协会成员在这个地区提供了一个化石记录的一个预先存在的巨大分子云复杂。由于猎户座λ H II区域的作用，来自原始复合体的气体最近已从这些恒星附近移走，目前被检测为围绕H II区域的大质量壳层。更多»壳层质量和H II质量的估计。阿尔法帽。复合体中的发射天体和OB星使得能够确定总的恒星形成效率：我们发现为0.2%：0.3%。如此低的效率可能是巨型分子云复合体的特征。我们发现的低恒星形成效率表明，绝大多数的原始结合质量的λ猎户座复合物已经消散，留下最近形成的恒星。因此，我们期望这种关联是不受约束的和扩展的。«少
We have made a well-sampled and deep survey for H..cap alpha.. emission objects in a region about 100 square degrees in area (about 5000 pc/sup 2/), centered on the lambda Orionis OB association. We detected 83 objects, of which 62 were previously known from earlier, less extensive surveys. The majority of the H..cap alpha.. emission objects in this region are not projected against dark cloud material, an many appear to be within the central regions of the extended (i.e., about 6/sup 0/ in diameter) low density H II region excited by lambda/sup 1/ Orionis. The vast majority of the H..cap alpha.. emission objects form an elongated, barlike structure 2/sup 0/ x 8/sup 0/ in extent. These dimensions are similar to those of giant molecular cloud complexes which spawn OB and T associations. We suggest that the spatial distribution of H..cap alpha.. emission objects and OB association members in this region provides a fossil record of a preexistent giant molecular cloud complex. The gas from the original complex has been recently removed from the vicinity of these stars by the action of the lambda Orionis H II region and is presently detected as a massive shell surrounding the H II region.more » Estimates of the mass of the shell and of the mass of the H..cap alpha.. emission objects and OB stars in the complex enable a determination to be made of the total star-formation efficiency: which we find to be 0.2%: 0.3%. Such low efficiency may be characteristic of giant molecular cloud complexes. The low star-formation efficiency we find suggests that the vast majority of the original binding mass of the lambda Orionis complex has been dissipated, leaving recently formed stars behind. Consequently, we expect this association to be unbound and expanding.« less