大质量恒星强烈的反馈深刻影响其周围的星际介质,并可能触发下一代恒星形成.S187是位于银河系第2象限的大质量恒星形成区,呈现出“扫集-坍缩”的触发式恒星形成模式.基于“银河画卷”巡天^(12)CO/^(13)CO/C^(18)O(J=1-0,下文J=1-0为简...大质量恒星强烈的反馈深刻影响其周围的星际介质,并可能触发下一代恒星形成.S187是位于银河系第2象限的大质量恒星形成区,呈现出“扫集-坍缩”的触发式恒星形成模式.基于“银河画卷”巡天^(12)CO/^(13)CO/C^(18)O(J=1-0,下文J=1-0为简便起见省略)谱线数据,对S187区域分子云的基本性质开展了研究,探索了该区域大质量恒星对分子云的反馈.利用GaussPy+和聚类算法,在该区域证认了32个分子云,并结合Gaia(Global Astrometric Interferometer for Astrophysics)卫星恒星消光数据测量得到其中8个分子云的距离.S187区域由^(13)CO和C^(18)O示踪的相对致密的气体含量相比于银道面第2象限大部分区域的分子云高出1–2个量级.S187区域分子云中证认了243个^(13)CO团块和98个C^(18)O团块,其中有7个^(13)CO团块和5个C^(18)O团块有形成大质量恒星的潜力.研究结果显示,大质量恒星的反馈对其周围分子云的聚集作用明显,为下一代大质量恒星的形成提供了条件.展开更多
By simple arguments, it is shown how alkaline types of atoms can be seen in dense molecular clouds depending on the average temperature of such regions of the Universe. This paper predicts infrared lines of such atoms...By simple arguments, it is shown how alkaline types of atoms can be seen in dense molecular clouds depending on the average temperature of such regions of the Universe. This paper predicts infrared lines of such atoms that could be seen in molecular clouds. The theory is developed in the first part and the predicted experimental results will follow. It results that the alkaline atoms modelized using the short-range polarization potential are found in quantum states <em>n</em><sub>*</sub> > 2.展开更多
HOCN and HNCO abundance ratio in molecular gas can tell us the information of their formation mechanism.We performed high-sensitivity mapping observations of HOCN,HNCO,and HNC^(18)O lines around Sagittarius B2(Sgr B2)...HOCN and HNCO abundance ratio in molecular gas can tell us the information of their formation mechanism.We performed high-sensitivity mapping observations of HOCN,HNCO,and HNC^(18)O lines around Sagittarius B2(Sgr B2)with the IRAM 30 m telescope at the 3 mm wavelength.HNCO 4_(04)-3_(03)and HOCN 4_(04)-3_(03)are used to obtain the abundance ratio of HNCO to HOCN.The ratio of HNCO 4_(04)-3_(03)to HNC^(18)O 4;-3;is used to calculate the optical depth of HNCO 4_(04)-3_(03).The abundance ratio of HOCN and HNCO is observed to range from 0.4%to0.7%toward most positions,which agrees well with the gas-grain model.However,the relative abundance of HOCN is observed to be enhanced toward the direction of Sgr B2(S),with HOCN to HNCO abundance ratio of~0.9%.The reason for that still needs further investigation.Based on the intensity ratio of HNCO and HNC^(18)O lines,we updated the isotopic ratio of;O/;O to be 296±54 in Sgr B2.展开更多
本文根据NGC7538的红外和分子谱线观测结果,对红外源的热结构及成协气体的热平衡进行了计算和分析。得出尘埃温度随半径的分布T_d a r^(-0.36)其峰值温度略高于已有观测结果,并发现除中心源附近区域外,大部分区域内不再满足尘埃通过碰...本文根据NGC7538的红外和分子谱线观测结果,对红外源的热结构及成协气体的热平衡进行了计算和分析。得出尘埃温度随半径的分布T_d a r^(-0.36)其峰值温度略高于已有观测结果,并发现除中心源附近区域外,大部分区域内不再满足尘埃通过碰撞向气体输入能量的基本条件。本文计算了NGC7538气体的冷却串及多种机制的加热作用,结果表明宇宙线、坍缩及双极扩散等机制的加热率相对较小,而尘埃通过光电作用对气体的加热可能是气体的重要热源。展开更多
文摘大质量恒星强烈的反馈深刻影响其周围的星际介质,并可能触发下一代恒星形成.S187是位于银河系第2象限的大质量恒星形成区,呈现出“扫集-坍缩”的触发式恒星形成模式.基于“银河画卷”巡天^(12)CO/^(13)CO/C^(18)O(J=1-0,下文J=1-0为简便起见省略)谱线数据,对S187区域分子云的基本性质开展了研究,探索了该区域大质量恒星对分子云的反馈.利用GaussPy+和聚类算法,在该区域证认了32个分子云,并结合Gaia(Global Astrometric Interferometer for Astrophysics)卫星恒星消光数据测量得到其中8个分子云的距离.S187区域由^(13)CO和C^(18)O示踪的相对致密的气体含量相比于银道面第2象限大部分区域的分子云高出1–2个量级.S187区域分子云中证认了243个^(13)CO团块和98个C^(18)O团块,其中有7个^(13)CO团块和5个C^(18)O团块有形成大质量恒星的潜力.研究结果显示,大质量恒星的反馈对其周围分子云的聚集作用明显,为下一代大质量恒星的形成提供了条件.
文摘By simple arguments, it is shown how alkaline types of atoms can be seen in dense molecular clouds depending on the average temperature of such regions of the Universe. This paper predicts infrared lines of such atoms that could be seen in molecular clouds. The theory is developed in the first part and the predicted experimental results will follow. It results that the alkaline atoms modelized using the short-range polarization potential are found in quantum states <em>n</em><sub>*</sub> > 2.
基金supported by the National Natural Science Foundation of China(11773054 and U1731237)supported by the international partnership program of Chinese Academy of Sciences through Grant No.114231KYSB20200009。
文摘HOCN and HNCO abundance ratio in molecular gas can tell us the information of their formation mechanism.We performed high-sensitivity mapping observations of HOCN,HNCO,and HNC^(18)O lines around Sagittarius B2(Sgr B2)with the IRAM 30 m telescope at the 3 mm wavelength.HNCO 4_(04)-3_(03)and HOCN 4_(04)-3_(03)are used to obtain the abundance ratio of HNCO to HOCN.The ratio of HNCO 4_(04)-3_(03)to HNC^(18)O 4;-3;is used to calculate the optical depth of HNCO 4_(04)-3_(03).The abundance ratio of HOCN and HNCO is observed to range from 0.4%to0.7%toward most positions,which agrees well with the gas-grain model.However,the relative abundance of HOCN is observed to be enhanced toward the direction of Sgr B2(S),with HOCN to HNCO abundance ratio of~0.9%.The reason for that still needs further investigation.Based on the intensity ratio of HNCO and HNC^(18)O lines,we updated the isotopic ratio of;O/;O to be 296±54 in Sgr B2.
文摘本文根据NGC7538的红外和分子谱线观测结果,对红外源的热结构及成协气体的热平衡进行了计算和分析。得出尘埃温度随半径的分布T_d a r^(-0.36)其峰值温度略高于已有观测结果,并发现除中心源附近区域外,大部分区域内不再满足尘埃通过碰撞向气体输入能量的基本条件。本文计算了NGC7538气体的冷却串及多种机制的加热作用,结果表明宇宙线、坍缩及双极扩散等机制的加热率相对较小,而尘埃通过光电作用对气体的加热可能是气体的重要热源。
