阿塔卡马大型毫米波/亚毫米波阵列-夸克巡天：大质量原星团IRAS 17233-3606中热分子碎片的性质
The ALMA-QUARKS Survey: Properties of Hot Molecular Fragments in the Massive Protocluster IRAS 17233-3606
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中文总结 AI 辅助
研究大质量原星团IRAS 17233-3606热分子核内碎裂机制，利用ALMA数据详细分析，揭示热核及碎片情况，结合相关参数表明其演化情景，指出恒星和HII区反馈影响形态化学性质，突出高质量原星团中多样物理过程作用。
中文摘要 AI 辅助
为了研究大质量原星团IRAS 17233-3606（G351.78-0.54）热分子核内的碎裂物理机制，我们利用了来自ATOMS巡天的阿塔卡马大型毫米波/亚毫米波阵列（ALMA）波段3数据和夸克巡天的波段6数据，对连续谱和谱线进行了详细分析。低分辨率3毫米数据揭示了一个质量约为81.3太阳质量的大质量热核MM1和一个显著的超紧凑（UC）HII区MM2，而高分辨率数据将MM1分解为11个热分子碎片（HMF）。这些HMF表现出高温（转动温度Trot = 100-310 K）的CH3CN和CH3OH发射以及高柱密度（NH2 > 10^23 cm^-2），表明它们有形成大质量恒星的潜力。基于外流、脉泽、HII区和f[CH3CN/CH3O]丰度比，11个HMF的演化序列被分类为I至IV阶段。HMF的平均最小生成树（MST）间距（约1.8 x 10^3天文单位）几乎是热金斯长度（约3.3 x 10^3天文单位）的一半。结合MM1的Q参数Q = 0.77和维里参数alpha_vir = 0.84，这些结果表明了一种演化情景，即碎裂最初由热不稳定性驱动，随后是整体引力收缩，并通过活跃吸积增长。同时，B2型零龄主序（ZAMS）恒星和UC HII区的反馈显著影响了MM1和MM2的形态和化学性质。这种不均匀性突出了在高质量原星团中发生的各种物理过程的作用。
英文摘要
To investigate the physical mechanisms of fragmentation within the hot molecular core of the massive protocluster IRAS 17233-3606 (G351.78-0.54), we carried out a detailed analysis of continuum and lines, using the ALMA Band 3 data from the ATOMS survey and Band 6 data from the QUARKS survey. The low-resolution 3 mm data reveal a massive hot core MM1 with a mass of ~81.3 Msun, and a prominent ultracompact (UC) HII region MM2, while the high-resolution data resolve MM1 into 11 hot molecular fragments (HMFs). These HMFs exhibit hot (Trot = 100-310 K) CH3CN and CH3OH emission and high column densities (NH2 > 10^23 cm^-2), indicating their potential to form massive stars. Based on outflows, masers, HII regions, and f[CH3CN/CH3O] abundance ratios, the evolutionary sequences of the 11 HMFs are categorized as phases I to IV. The mean minimum-spanning tree (MST) separation (~1.8 x 10^3 au) of the HMFs is nearly half of the thermal Jeans length (~3.3 x 10^3 au). Together with the Q parameter Q = 0.77 and virial parameter alpha_vir = 0.84 of MM1, these results suggest an evolutionary scenario in which fragmentation is initially driven by thermal instability, followed by global gravitational contraction and growth through active accretion. Meanwhile, feedback from the B2-type zero-age main-sequence (ZAMS) star and the UC HII region significantly influence the morphology and chemical properties of MM1 and MM2. This heterogeneity highlights the role of diverse physical processes taking place in high-mass protoclusters.
