AI 中文总结
研究中岛-出木对象这一神秘天体，通过多望远镜观测其毫米波连续谱和分子线发射，经SED拟合等分析其参数、谱线及外流形态，发现其与恒星形成环境相关，推测它可能是距离约远十倍的猎户座KL类似物。
AI 中文摘要
中岛-出木对象（NDO，又名IRAS 19312+1950）被认为是一个神秘物体，兼具演化恒星和恒星形成区域的特征，但其实际性质仍在争论中。我们使用IRAM-30米、APEX望远镜以及SMA对该物体进行了（亚）毫米波连续谱和分子线发射观测。基于单 dish连续谱观测的SED拟合，确定了承载NDO的云团的尘埃温度等参数。SMA连续谱观测将云团解析为至少四个尘埃连续谱核心，核心MM1是主要质量储库。单 dish光谱观测检测到59条谱线，SMA光谱观测在MM1检测到75条谱线。观测到的高速外流与球形形态不符，更像是广角双极外流。氘化物种的存在等表明NDO周围物质与恒星形成环境更相关，推测该神秘物体可能是距离约远十倍的猎户座KL类似物。
英文摘要
The Nakashima-Deguchi object (NDO; aka IRAS 19312+1950) has been recognized as an enigmatic object, exhibiting characteristics of both an evolved star and a star-forming region. However, the actual nature of this object remains a topic of ongoing debate. We conducted observations of this object in (sub)millimeter continuum and molecular line emission using the IRAM-30m and APEX telescopes as well as the SMA. Based on SED fitting of single-dish continuum observations, we determined that the cloud hosting NDO has a dust temperature of $25\pm2$ K, a source-averaged (24$^{\prime\prime}$) H$_2$ column density of $(4.4\pm 0.6) \times 10^{22}$ cm$^{-2}$, a dust emissivity index of $1.7\pm0.2$, and a total gas mass of $220\pm21 M_{\odot}$. SMA continuum observations resolve the cloud into at least four dust continuum cores. The centrally peaked core MM1, associated with an SiO maser, is the primary mass reservoir. Single-dish spectroscopic observations of NDO led to the detection of 59 spectral lines attributed to 12 species and their isotopologues. This includes the first detection of deuterated molecules, DCO$^{+}$, DCN, DNC, and HDCO, indicating substantial deuterium abundance. SMA spectroscopic observations detected 75 spectral lines toward MM1, assigned to 12 species and their isotopologues. These lines exhibit diverse morphologies on a scale of $\sim$0.1 pc, likely due to outflow feedback. The observed high-velocity outflow is inconsistent with a spherical morphology and rather resembles a wide-angle bipolar outflow. The presence of deuterated species, and the overall large mass of the complex, the surrounding material of NDO appears more naturally associated with a star-forming environment than with a purely evolved-star scenario. Our investigations led us to postulate that this enigmatic object may represent an Orion KL analog about ten times farther away.
Commentsaccepted for publication in A&A; the interactive version of the 3D view of the outflow can be accessed via https://gongyan2444.github.io/NDO-CO21-SMA-APEX-3D.html
