大質量星團形成環境中的噴流性質統計

Statistical properties of molecular outflows in a massive cluster-forming environment

劉欣旻(Hsin-Min Liu)

指導教授 ： 陳惠茹

國立清華大學/理學院/天文研究所/碩士(2021年)

摘要

大質量恆星的一生都影響著星系的演化。他們會在恆星形成的環境中提供強大的輻射和金屬。然而，我們至今仍然不知道大質量恆星是如何形成的。根據initial mass function，我們知道大質量恆星會和其他較小質量的恆星一起在星團中形成。在恆星形成的早期階段，會產生分子噴流。噴流可以讓我們得知原恆星在吸積過程時的性質。本論文中，我們計算了在大質量星團形成環境(G33.92+0.11)裡35個噴流的性質。我們使用一個名為Rolling Hough Transfrom的直線辨識演算法得到噴流在天球上的方向。在這些噴流中，有17個噴流能對到Suárez et al. (2021)中提供的核。我們也和其他研究噴流的論文做比較。我們得到用X＿sio=10^(-9)算出來的結果和其他論文較一致，而我們並沒有發現噴流的性質和其核質量有明顯的關聯。我們需要利用 其他的分子來了解大質量恆星形成。

關鍵字

恆星形成 ； 噴流 ； 星團

並列摘要

The life cycle of high-mass stars affects galaxy evolution. High-mass stars provide strong radiation and metal in the star-forming environment. However, we do not know how a massive star forms. According to the initial mass function, we know that massive stars might form in a cluster with other low-mass stars. The early stages of star formation produce molecular outflows. Outflows provide the properties of the accretion process of the protostars. In this thesis, we present the properties of 35 SiO(5-4) outflows in the massive cluster-forming cloud G33.92+0.11. We identify outflows with the Rolling Hough Transform (RHT), an algorithm used for identifying linear structures and determining their orientation in a 2D image. In Total, 17 outflow
lobes can match with cores identified in Suárez et al. (2021). We calculate the SiO column density, SiO luminosity, mass, momentum, energy, dynamical time-scale, mass-loss rate, and force for all identified outflows. Finally, we compare our results with those values in the literature. Previous results are consistent with our data using
X_sio = 10^(-9). In the current analysis, we do not find a strong correlation between the outflow properties and the physical conditions of the cores. We suggest using other tracers for outflow to understand the high-mass star formation.

並列關鍵字

star formation ； outflow ； cluster

參考文獻

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