AI 中文总结
本研究通过ALMA与VLA观测结合档案数据，统计金牛座原恒星多重性，发现其多重性显著高于猎户座、英仙座，暗示金牛座保留更多原始多重系统，且存在两种不同形成途径。
AI 中文摘要
我们呈现了对金牛座分子云（TMC）中25个原恒星系统的新ALMA 0.9毫米和VLA 9毫米观测，这些系统包含40颗原恒星，观测分辨率为0.3角秒（约20天文单位）。在18至10000天文单位的间距范围内，ALMA/VLA观测的金牛座样本的多重性分数（MF，定义为至少包含一个伴星的系统占比）为0.50±0.07，伴星分数（CF，定义为每个系统的平均伴星数量）为0.58±0.20。为了更完整地统计该区域的原恒星多重性，我们补充了24颗原恒星（12个原恒星系统及与观测系统相关的5个额外伴星），这些原恒星是此前通过档案红外观测或ALMA观测识别的。这64颗原恒星（37个系统）共同构成了我们的金牛座+样本，我们测得其MF和CF分别为0.53±0.06和0.72±0.19，数值更高。TMC中的这些多重性统计值，与更密集的猎户座和英仙座恒星形成区域报告的数值相比，在约3至4倍标准差水平上显著更高，表明金牛座可能保留了更大比例的原始多重系统。我们样本的间距分布显示出密近和宽距多重系统的群体，但在200至300天文单位的中间间距存在缺失，该模式可能暗示两种不同的形成途径：密近双星（<200天文单位）主要源于盘碎裂，宽距多重系统（>1000天文单位）源于核碎裂。
英文摘要
We present new ALMA 0.9 mm and VLA 9 mm observations in the Taurus Molecular Cloud (TMC) of 25 protostellar systems, containing 40 protostars, observed at 0.3" (~20 au) resolution. Within separations of 18-10,000 au, the ALMA/VLA-observed Taurus sample has a multiplicity fraction (MF), defined as the fraction of systems with at least one companion, of 0.50 +/- 0.07, and a companion fraction (CF), defined as the average number of companions per system, of 0.58 +/- 0.20. To build a more complete census of protostellar multiplicity in this region, we supplement the observed sample with 24 protostars (12 protostellar systems and 5 additional companions associated with systems we observed) previously identified through archival infrared or ALMA observations. Together, these 64 individual protostars (37 systems) define our Taurus+ sample, for which we measure higher values of 0.53 +/- 0.06 and 0.72 +/- 0.19 for the MF and CF, respectively. These multiplicity statistics in the TMC are notably higher than those reported in the more clustered star-forming regions of Orion and Perseus at the ~3-4 sigma level, suggesting that Taurus may preserve a larger fraction of primordial multiples. The separation distributions in our samples show populations of both close and wide multiples, but a deficit at intermediate separations of 200-300 au. This pattern may suggest two distinct formation pathways: close binaries (<200 au) arising primarily from disk fragmentation, and wide multiples (>1000 au) from core fragmentation.
