CLUSTER FORMATION TRIGGERED BY FILAMENT COLLISIONS IN SERPENS SOUTH
CLUSTER FORMATION TRIGGERED BY FILAMENT COLLISIONS IN SERPENS SOUTH
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DOI：
10.1088/2041-8205/791/2/l23
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发表时间：
2014-07
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通讯作者：
F. Nakamura;K. Sugitani;Tomohiro Tanaka;H. Nishitani;K. Dobashi;T. Shimoikura;Y. Shimajiri;R. Kawabe;Y. Yonekura;I. Mizuno;K. Kimura;K. Tokuda;M. Kozu;N. Okada;Yutaka Hasegawa;H. Ogawa;S. Kameno;H. Shinnaga;M. Momose;T. Nakajima;T. Onishi;H. Maezawa;T. Hirota;S. Takano;D. Iono;N. Kuno;S. Yamamoto
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文献类型：
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作者：
F. Nakamura;K. Sugitani;Tomohiro Tanaka;H. Nishitani;K. Dobashi;T. Shimoikura;Y. Shimajiri;R. Kawabe;Y. Yonekura;I. Mizuno;K. Kimura;K. Tokuda;M. Kozu;N. Okada;Yutaka Hasegawa;H. Ogawa;S. Kameno;H. Shinnaga;M. Momose;T. Nakajima;T. Onishi;H. Maezawa;T. Hirota;S. Takano;D. Iono;N. Kuno;S. Yamamoto
巨蛇座南红外暗云由几个冰脊组成，其中一些分裂成密集的团块。根据CCS（JN = 43-32）、HC_3 N（J = 5-4）、N_2H ~+（J = 1-0）和SiO（J = 2-1，v = 0）的观测资料，研究了这些洋脊的运动学和化学演化。我们发现，CCS是非常丰富的沿着主丝在原星团。我们强调，Serpens南部是第一个检测到非常强的CCS排放的集群形成区域。在原团簇中，CCS与N2 H+的丰度比估计约为0.5，而在主丝的其他部分约为3。我们确定了六个密集的脊与不同的VLSR。这些脊似乎向原星团聚集，表明这些脊的碰撞可能触发了星团的形成。碰撞大概发生在几× 105年之内，因为CCS的丰度只在很短的时间内。短的寿命与I类天体的数量比例（典型寿命为0.4 × 105年）非常高的事实相一致，在原星团中约占70%。在北方，两个脊似乎部分碰撞，形成一个V形团块。此外，我们还探测到了强的双极SiO发射，这是由于分子流出吹出的原恒星团，以及扩展的弱SiO发射，可能源于灯丝碰撞。
The Serpens South infrared dark cloud consists of several filamentary ridges, some of which fragment into dense clumps. On the basis of CCS (JN = 43–32), HC3N (J = 5–4), N2H+ (J = 1–0), and SiO (J = 2–1, v = 0) observations, we investigated the kinematics and chemical evolution of these filamentary ridges. We find that CCS is extremely abundant along the main filament in the protocluster clump. We emphasize that Serpens South is the first cluster-forming region where extremely strong CCS emission is detected. The CCS-to-N2H+ abundance ratio is estimated to be about 0.5 toward the protocluster clump, whereas it is about 3 in the other parts of the main filament. We identify six dense ridges with different VLSR. These ridges appear to converge toward the protocluster clump, suggesting that the collisions of these ridges may have triggered cluster formation. The collisions presumably happened within a few × 105 yr because CCS is abundant only for a short time. The short lifetime agrees with the fact that the number fraction of Class I objects, whose typical lifetime is 0.4 × 105 yr, is extremely high, about 70% in the protocluster clump. In the northern part, two ridges appear to have partially collided, forming a V-shape clump. In addition, we detected strong bipolar SiO emission that is due to the molecular outflow blowing out of the protostellar clump, as well as extended weak SiO emission that may originate from the filament collisions.