Discovery of a Massive Protostar near IRAS 18507+0121
Discovery of a Massive Protostar near IRAS 18507+0121
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DOI：
10.1086/381050
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发表时间：
2003-10
期刊：
影响因子：
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通讯作者：
D. Shepherd;D. Nürnberger;L. Bronfman
中科院分区：
文献类型：
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作者：
D. Shepherd;D. Nürnberger;L. Bronfman
我们观测到了大质量恒星形成区IRAS 18507+0121的3 mm连续发射、H13CO+ (J = 1-0)和SiO （v = 0, J = 2-1）线发射以及1.2 ~ 2.1 μm的近红外（NIR）发射。检测到两个紧凑的分子核：一个北一个南，间隔约40”。北部分子核心包含一颗新发现的深嵌的B2原恒星，G34.4+0.23 MM，周围环绕着数百太阳质量的温暖气体和尘埃。基于热尘埃发射的存在和近红外波长检测的缺乏，我们认为G34.4+0.23 MM可能代表了一颗相对罕见的大质量原恒星（例如，类似于低质量的“0级”原恒星）。南部的分子核心与一个由年轻恒星组成的近红外星团和一个超紧凑的H II区有关，G34.4+0.23，中央有一颗B0.5恒星。具有过量红外辐射的近红外恒星的比例大于50%，这表明IRAS 18507+0121恒星形成区的年龄上限为3myr。
We have observed the massive star-forming region IRAS 18507+0121 at millimeter wavelengths in 3 mm continuum emission, H13CO+ (J = 1-0) and SiO (v = 0, J = 2-1) line emission, and at near-infrared (NIR) wavelengths between 1.2 and 2.1 μm. Two compact molecular cores are detected: one north and one south, separated by ~40''. The northern molecular core contains a newly discovered, deeply embedded, B2 protostar surrounded by several hundred solar masses of warm gas and dust, G34.4+0.23 MM. Based on the presence of warm dust emission and the lack of detection at NIR wavelengths, we suggest that G34.4+0.23 MM may represent the relatively rare discovery of a massive protostar (e.g., analogous to a low-mass "Class 0" protostar). The southern molecular core is associated with an NIR cluster of young stars and an ultracompact H II region, G34.4+0.23, with a central B0.5 star. The fraction of NIR stars with excess infrared emission indicative of circumstellar material is greater than 50%, which suggests an upper limit on the age of the IRAS 18507+0121 star-forming region of 3 Myr.