The JCMT Legacy Survey of the Gould Belt: a first look at Taurus with HARP
The JCMT Legacy Survey of the Gould Belt: a first look at Taurus with HARP
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DOI：
10.1111/j.1365-2966.2010.16499.x
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发表时间：
2010-02
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通讯作者：
C. Davis;A. Chrysostomou;J. Hatchell;J. Wouterloot;J. Buckle;D. Nutter;M. Fich;C. Brunt;H. Butner;B. Cavanagh;E. Curtis;A. Duarte-Cabral;J. Francesco;M. Etxaluze;P. Friberg;R. Friesen;G. Fuller;S. Graves;J. Greaves;M. Hogerheijde;D. Johnstone;B. Matthews;H. Matthews;J. Rawlings;J. Richer;J. Roberts;S. Sadavoy;R. Simpson;N. Tothill;Y. Tsamis;S.Viti;D. Ward-Thompson;G. White;J.Yates
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文献类型：
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作者：
C. Davis;A. Chrysostomou;J. Hatchell;J. Wouterloot;J. Buckle;D. Nutter;M. Fich;C. Brunt;H. Butner;B. Cavanagh;E. Curtis;A. Duarte-Cabral;J. Francesco;M. Etxaluze;P. Friberg;R. Friesen;G. Fuller;S. Graves;J. Greaves;M. Hogerheijde;D. Johnstone;B. Matthews;H. Matthews;J. Rawlings;J. Richer;J. Roberts;S. Sadavoy;R. Simpson;N. Tothill;Y. Tsamis;S.Viti;D. Ward-Thompson;G. White;J.Yates
作为詹姆斯·克莱克·麦克斯韦望远镜(JCMT)对古尔德带恒星形成的遗留调查的一部分，我们介绍了金牛座的早期科学结果。沿着西北海脊和碗获得了CO J=3-2图，统称为L 1495，并在两个亚区获得了深部13CO和C18O J=3-2图。利用这些数据，我们搜索了分子外流，并使用流的分布、HerBig-Haro(HH)天体和受冲击的H2线发射特征，以及年轻恒星、原恒星核心和无恒星凝聚的数量，来绘制这一广泛区域的恒星形成图。总共确定了21项资金外流。很明显，碗比山脊进化得更多，拥有更多的金牛座T星，以及更分散、更动荡的环境介质。相比之下，海脊包含了更年轻、分布更广的原恒星群体，而这反过来又与更多的分子外流有关。我们估计L 1495年的恒星前核与原恒星核的数目之比为∼1.3-2.3，无引力束缚的无恒星核与(引力束缚的)前恒星核的比率为∼1。期刊汇编C©2010 RAS 760 C.J.Davis等人。在∼的5×105年原恒星寿命中，恒星前寿命为9(±3)×105年。根据流出的数量，我们还粗略地估计了L 1495年的恒星形成效率，发现它与10%-15%的典范值是一致的。我们注意到，分子外流驱动源比HH喷气驱动源具有更红的近红外颜色。我们还发现，更小、更密集的核心与更大质量的外流有关，如果流中的质量积累随着原恒星包层的坍塌和收缩而增加，人们可能会预料到这一点。
As part of a James Clerk Maxwell Telescope (JCMT) Legacy Survey of star formation in the Gould Belt, we present early science results for Taurus. CO J = 3–2 maps have been secured along the north-west ridge and bowl, collectively known as L 1495, along with deep 13CO and C18O J = 3–2 maps in two subregions. With these data, we search for molecular outflows, and use the distribution of flows, Herbig–Haro (HH) objects and shocked H2 line-emission features, together with the population of young stars, protostellar cores and starless condensations to map star formation across this extensive region. In total, 21 outflows are identified. It is clear that the bowl is more evolved than the ridge, harbouring a greater population of T Tauri stars and a more diffuse, more turbulent ambient medium. By comparison, the ridge contains a much younger, less widely distributed population of protostars which, in turn, is associated with a greater number of molecular outflows. We estimate the ratio of the numbers of prestellar to protostellar cores in L 1495 to be ∼1.3–2.3, and of gravitationally unbound starless cores to (gravitationally bound) pre-stellar cores to be ∼1. If we take previous estimates E-mail: cjd@jach.hawaii.edu C © 2010 The Authors. Journal compilation C © 2010 RAS 760 C. J. Davis et al. of the protostellar lifetime of ∼5 × 105 yr, this indicates a pre-stellar lifetime of 9(±3) × 105 yr. From the number of outflows, we also crudely estimate the star formation efficiency in L 1495, finding it to be compatible with a canonical value of 10–15 per cent. We note that molecular outflow-driving sources have redder near-infrared colours than their HH jet-driving counterparts. We also find that the smaller, denser cores are associated with the more massive outflows, as one might expect if mass build-up in the flow increases with the collapse and contraction of the protostellar envelope.